Network Security Lecture Notes

the world runs on data off the internet houses are treasured loop of potentially harmful information from basic shopping habits to private financial transactions all this data is carried over a network of interconnected devices during transit the data is as secure as the mechanism responsible for its transmission it's in this phase that the most corrupted data originates it's paramount that the networks carrying this data must be secured against malicious hackers and ample attacks let's take a look at the topics to be covered in this video on network security which is rising in popularity and importance we start by introducing the viewers to network security and its basic definition we cover the working of network security in the next section then we have the different types of network security followed by a small introduction to transport and application layer security and the importance next we cover the key tools in network security the benefits and a live demonstration of how nmap can scan posts and aid in ethical hacking so let's start with the first topic for the day which is an introduction to network security network security is a set of technologies that protects the usability and integrity of a company's infrastructure by preventing the entry or proliferation within a network it architecture comprises of tools that protect the network itself and the applications that run over it effective network security strategies employ multiple lines of defense that are scalable and automated each defensive layer here enforces a set of security policies which are determined by the administrator beforehand this aims at securing the confidentiality and accessibility of the data and the network the every company or organization that handles a large amount of data has a degree of solutions against many cyber threats the most basic example of network security is password protection it has the network the user chooses recently network security has become the central topic of cyber security with many organizations involving applications from people with skills in this area it is crucial for both personal and professional networks most houses with high speed internet have one or more wireless routers which can be vulnerable to attacks if they are not adequately secured data loss theft and sabotage risk may be decreased with the usage of a strong network security system the workstations are protected from hazardous spyware thanks to network security additionally it guarantees the security of the data which is being shared over a network by dividing information into various sections encrypting these portions and transferring them over separate pathways network security infrastructure offers multiple levels of protection to thought man in the middle attacks preventing situations like eavesdropping among other harmful attacks it is becoming increasingly difficult in today's hyper-connected environment as more corporate applications migrate to both public and private clouds additionally modern applications are also frequently virtualized and dispersed across several locations some outside the physical control of the itd network traffic and infrastructure must be protected in these cases since assaults on businesses are increasing every single day we now understood the basics of network security but we need to understand how network security works in the next section in slightly more detail network security revolves around two processes authentication and authorization the first process which is authentication is similar to access paths which ensure that only those have the right to enter a building in other words authentication checks and verifies that it is indeed the user belonging to the network who is trying to access or enter it thereby preventing unauthorized intrusions next comes authorization this process decides the level of access provided to the recently authenticated user for example network admin needs access to the entire network whereas those working within it probably need access to only certain areas within the network based on the network user's role the process of determining the level of access or permission level is known as authorization today's network architecture is complex and faces a threat environment that is always changing and attackers that are always trying to find and exploit vulnerabilities these vulnerabilities can exist in many areas including devices data applications users and locations for this reason many network security management tools and applications are in use today that address individual threats when just a few minutes of down times can cause widespread disruption and massive damage to an organization's bottom line and reputation it is essential that these protection measures are in place beforehand now that we know a little about network security and it's working let's cover the different types of network security the fundamental tenet of network security is the layering protection for massive networks and stored data that ensure the acceptance of rules and regulations as a whole there are three types the first of which is physical security the next being technical and the third being administrative let's look into physical security first this is the most basic level that includes protecting data and network through unauthorized personnel from acquiring control over the confidentiality of the network these include external peripherals and routers that might be used for cable connections the same can be achieved by using devices like biometric systems physical security is critical especially for small businesses that do not have many resources to devote to security personnel and the tools as opposed to large firms when it comes to technical network security it focuses mostly on safeguarding data either kept in the network or engaged in network transitions this kind fulfills two functions one is depends against unauthorized users the other is a defense against malevolent actions the last category is administrative this level of network security protects user behavior like how the permission has been granted and how the authorization process takes place this also ensures the level of sophistication the network might need to protect it through all the attacks this level also suggests necessary amendments that have to be done to the infrastructure i think that's all the basics that we need to cover on network security in which our next topic we're going to go through two mediums of network security which are the transport layer and the application layer the transport layer is a way to secure information as it is carried over the internet with users browsing websites emails instant messaging etc tls aims to provide a private and secure connection between a web browser and a website server it does this with a cryptographic handshake between two systems using public key cryptography the two parties through the connection exchange a secret token and once each machine validates this token it is used for all communications the connection employs lighter symmetric cryptography to save bandwidth and processing power since the application layer is the closest layer to the end user it provides hackers with the largest threat surface poor app layer security can lead to performance and stability issues data theft and in some cases the network being taken down examples of application layer attacks include distributed denial of service attacks or tdos attacks http flats hp injections cross-site scripting etc most organizations have an arsenal of application layer security protections to combat these and more such as web application firewalls secure web gateway services etc now that we have the theory behind network security has been covered in detail let us go through some of the tools that can be used to enforce these network security policies the first two to be covered in the section is a firework a firewall is a type of network security device that keeps track of incoming and outgoing network traffic and it decides which traffic to allow or deny in accordance to a set of security rules for more than 25 years firewalls have served a network security's first line of defense they provide a barrier between trustworthy internal protected and regulated networks from shady external networks like the internet at some point the next tool which can be used to bolster network security is a virtual private network or vpn for short it's an encrypted connection between a device and a network via the internet the encryptment connection is the secure transmission of sensitive data it makes it impossible for unauthorized parties to eavesdrop on the traffic and enables remote work for the user the usage of vpn technology is common in both corporate and personal networks next we cover the importance of inclusion prevention systems in network security or ips frameworks an intrusion prevention system is a network security tool that continually scans the network for harmful activity and responds to it when it does occur by reporting blocking or discarding it it can be either hardware or software it's more sophisticated than an inclusion detection system or an ids framework which can just warn an administrator and merely identify harmful activities while in the case of an ips it actually takes against that activity the next tool in this section and final one are going to be behavioral analytics behavior analytics focus more on the statistics that are being carried over and stored through months and years of usage when some kind of similar pattern is noted that the idea administrator can detect some kind of attack the similar attacks can be stopped and the security can be further enhanced another day i've covered all that we need to know about network security the necessary tools it's different types etc let's go through the benefits of network security as a whole the first which is protection against external threats the objective for cyber assaults can be as varied as the defenders themselves although they are typically initiated for financial gain whether they are industrial spies hacktivists or cyber criminals these bad actors all have one thing in common which is how quick clever and covert the attacks are getting a strong cyber security posture that considers routine software updates may assist firms in identifying and responding to the abuse techniques tools and the common entry points the next benefit is protection against internal threats the human aspect continues to be the cyber security system's weakest link insider risk can originate from current or former workers third party vendors or even trusted partners and they can be unintentional careless or downright evil aside from that the rapid expansion of remote work and the personal devices used for business purposes while even iot devices in remote locations can make it easier for these kind of threats to go undetected until it's too late however by proactively monitoring networks and managing access these dangers may be identified and dealt with before they become expensive disasters the third benefit is increased productivity it is nearly impossible for employees to function when network and personal devices are slowed to a crawl by viruses and other cyber attacks during the operation of website and for the company to run you must significantly minimize violations and the amount of downtime required to fix the breach by implementing various cybersecurity measures such as enhanced firewalls wireless scanning and automatic backups employee identification of possible email phishing schemes suspicious links and other malicious criminal activities can also be aided by education and training another benefit is brand trust and reputation customer retention is one of the most crucial elements in business development customers today place a premium on maintaining brand loyalty through a strong cyber security stance since this is the fastest way to get other businesses back get referrals and sell more tickets overall additionally it helps manufacturers get on the vendor list with bigger companies as a part of the supply chain which is only as strong as its weakest link this opens possibilities for potential future endeavors and development it's all really the all for the theoretical part of network security after covering so many topics let's go through a small demonstration to drive home this topic's importance so one of the first things we're going to cover is the installation of nmap what are we using right now is actually vmware a re-running an instance of a relax distribution known as parrot security operating system the parrot security os is a debian based linux distribution that is catered more towards ethical hackers and penetration testers the howard is created more is it comes pre-installed with a lot of tools that ethical hackers need including nmap so let's say you're using another debian based linux distribution if you want to install nmap you can go with the command of sudo apt which is the package manager install and and just press enter at this point it's going to ask you for your administrator password because of the sudo command which you have used now this epd will change depending on the distribution let's say using a distribution that is based on arch linux that will be different if there is some other distribution which is built from scratch the commands will differ but more or less a lot of the distributions the main stream distributions that people use like ubuntu zorinos max mint they are debian bs so you're just going to be using sudo apt install and map if you give your administrator password here it's going to see that nmap is smashed manually installed and it is already the newest version at this point if you do not have an app in your distribution it's going to install the necessary package files if i just use the nmap command you can see some help lines where it basically says what kind of flags you can use what are some of the most common commands the version etc it gives a small sample for the usage of nmap now the first one of the most basic functions of nmap is to identify active hosts on your network and app does this by using a ping scan or sometimes it's called a ping suite this identifies all of the ip addresses that are currently online without sending any packets to these hosts to run the command we're just going to go with let me just clear the screen for now another thing you have to do before running nmap just for our ease of use is we're going to use the sudo suv command this will turn our console into an administrator console so let's say we want to use some drivers or some external adapters or anything that requires administrative permission we don't have to use the admin password again and again just going to give it a bit of time for it to recognize okay now that you see uh this dollar sign has changed into a hash symbol which means we now have root access of this console right now of this terminal so what we're going to do for the pink suite where we have to check existing course is are going to use the command in map minus sp and go with the ip address of the current subnet that you are in which is always going to be minus one uh it's always going to be 192 and 168.1.1 the 24 bracket so this is going to take some time considering this is going to check all the hosts in this particular subnet the command then returns a list of posts on your network which is this and the total number of assigned ip addresses if you can spot like any ip addresses that you cannot account for in your network or your server you can then add further commands to investigate them further using nmap itself now coming to another feature of nmap which is a very important usage is when scanning posts and mac commands can use server names ip addresses or even ip6 addresses a basic nmap command will produce information about the given host so to run a basic port scan we can just use the nmap command with the ip address of the device or the ip address that we are targeting so for now the host machine that i am using currently has this current ip address if you can see the current id address is 192.168.1.22 as it's written in the ipv4 address preferred section so now we're going to try and attack this first machine using nmap on parent security operating system so we're just going to go with the end map 192 162 and press enter and it's going to start scanning the host for different services and the ap address that are being run on the system the speed of these scans usually depends on how quick the processor is and also how quickly the two machines can connect with each other but two machines i mean the virtual machine in this case and the machine that is being attacked which is right now the host machine which is running vmware workstation as you can see the core scanning is complete for this particular ip address and you can see the number of ports is mentioned and the services that these posts are used for is also mentioned it says which of these are open for example the 53 tcp port we can see it is closed while some of the other ports are open now one more feature of nmap is the ability to guess the operating system of the ip address that we are attacking for that we need to add one more flag which is going to go with the normal command is n map minus 4 and the regular appearance that we are in the process of attacking let's give it a few minutes to run the scan and it will try and put a small gas on the operating system that this host might be running this gas might not always be accurate but it puts a small idea and this is much more accurate in the case of actually unix based operating system other than windows based operating systems may be able to detect that if it is a windows a linux macintosh and so on but it may have difficulty finding exact single versions which becomes easier in the case of linux because we can identify different distributions by some of the kernels which and most of the vulnerabilities comes from the kernels and not the particular distributions as you can see the os detection guess is complete and you can see aggressive os is over here which is microsoft windows xp service pack or windows server and there's the 98 guess that it's mostly like i mentioned if you can guess if it is a windows based system you can apply the vulnerabilities and exploits accordingly now at times you may need to detect service version and the and similar information from these open ports actually this is useful for troubleshooting and scanning for vulnerabilities or locating services that need to be updated considering a lot of the new updates are used to fix these kind of open vulnerabilities so the flag that we're going to use in this case is minus sv or hyphen s3 so only this is going to change with the nmap and the ip address of the whole system staying consistent a lot of the services that are being run on these ports are often not the most safe for example apache web server which is a very common web server being used for even local and global projects uh a lot of the older versions used to have systems that can allow privilege escalations or other vulnerabilities that can allow hacker to get into your system without even you getting a trace of it silhouetted versions tend to fix these as quickly as possible and most of these versions do not circulate in the real world but can be used for ethical hacking and testing on how these validate and how these vulnerabilities can be attacked further now with the sv command scan is complete we can see that it is mentioning some of the version of the services that are being run on the particular post once again like i mentioned using these version numbers you can identify particular vulnerabilities and use the exploits design for these vulnerabilities to gain access to the system another thing that nmap does well is port scanning it's now the basic utilities actually that nmap offers and consequently there are few ways that this command can be customized further for example to come to start a port scan we're going to use the flag of my ipin p we're going to specify a random port for example 443 which we know it will be open because it is the port used for https connections which is obviously essential for you to access the internet and once again we are going to use the ip address or local host as the test machine that have been attacked as you can see it clearly states that the four fourth report is open as expected now you can use multiple ports you can check multiple ports this way for example and map and p we're going to use scan three different ports four four three eighty and four four five address again and it's going to show the state of all the three ports now you can see this filter part here which which does not mean it is open and it cannot be exploited in any way at least right now maybe there is any other service that is being run it can be exploited further but right now it is in a filtered condition that is how we can actually scan for multiple ports together we can also we can also use actually in a sports car in a range format for example let's say we're going to scan the ports from 200 to 300 and once again going to use the hyphen key flag then the ip address of the system being attacked it's going to scan all the posts from 200 to 300 and mention what are the ports that are open filtered or just straight up closed as you can see all the 101 stand posts are in ignore state for example if we try to scan a range in a more reasonable range for example uh 4 4 3 2 4 6 that's it we'll keep the ip address similar and you can see two of them are open and two of them are filtered for different different reasons this is how you can find out which of the ports are liable for exploitation before attacking these kind of devices hope you enjoy this video please let us know in the comments section if you have any issues with network security or the things that you learned in this video subscribe to our channel for more videos like this and thank you for watching [Music] hi there if you like this video subscribe to the simply learn youtube channel and click here to watch similar videos to nerd up and get certified click here

the world runs on data off the internet houses are treasured loop of potentially harmful information from basic shopping habits to private financial transactions all this data is carried over a network of interconnected devices during transit the data is as secure as the mechanism responsible for its transmission it&#39;s in this phase that the most corrupted data originates it&#39;s paramount that the networks carrying this data must be secured against malicious hackers and ample attacks let&#39;s take a look at the topics to be covered in this video on network security which is rising in popularity and importance we start by introducing the viewers to network security and its basic definition we cover the working of network security in the next section then we have the different types of network security followed by a small introduction to transport and application layer security and the importance next we cover the key tools in network security the benefits and a live demonstration of how nmap can scan posts and aid in ethical hacking so let&#39;s start with the first topic for the day which is an introduction to network security network security is a set of technologies that protects the usability and integrity of a company&#39;s infrastructure by preventing the entry or proliferation within a network it architecture comprises of tools that protect the network itself and the applications that run over it effective network security strategies employ multiple lines of defense that are scalable and automated each defensive layer here enforces a set of security policies which are determined by the administrator beforehand this aims at securing the confidentiality and accessibility of the data and the network the every company or organization that handles a large amount of data has a degree of solutions against many cyber threats the most basic example of network security is password protection it has the network the user chooses recently network security has become the central topic of cyber security with many organizations involving applications from people with skills in this area it is crucial for both personal and professional networks most houses with high speed internet have one or more wireless routers which can be vulnerable to attacks if they are not adequately secured data loss theft and sabotage risk may be decreased with the usage of a strong network security system the workstations are protected from hazardous spyware thanks to network security additionally it guarantees the security of the data which is being shared over a network by dividing information into various sections encrypting these portions and transferring them over separate pathways network security infrastructure offers multiple levels of protection to thought man in the middle attacks preventing situations like eavesdropping among other harmful attacks it is becoming increasingly difficult in today&#39;s hyper-connected environment as more corporate applications migrate to both public and private clouds additionally modern applications are also frequently virtualized and dispersed across several locations some outside the physical control of the itd network traffic and infrastructure must be protected in these cases since assaults on businesses are increasing every single day we now understood the basics of network security but we need to understand how network security works in the next section in slightly more detail network security revolves around two processes authentication and authorization the first process which is authentication is similar to access paths which ensure that only those have the right to enter a building in other words authentication checks and verifies that it is indeed the user belonging to the network who is trying to access or enter it thereby preventing unauthorized intrusions next comes authorization this process decides the level of access provided to the recently authenticated user for example network admin needs access to the entire network whereas those working within it probably need access to only certain areas within the network based on the network user&#39;s role the process of determining the level of access or permission level is known as authorization today&#39;s network architecture is complex and faces a threat environment that is always changing and attackers that are always trying to find and exploit vulnerabilities these vulnerabilities can exist in many areas including devices data applications users and locations for this reason many network security management tools and applications are in use today that address individual threats when just a few minutes of down times can cause widespread disruption and massive damage to an organization&#39;s bottom line and reputation it is essential that these protection measures are in place beforehand now that we know a little about network security and it&#39;s working let&#39;s cover the different types of network security the fundamental tenet of network security is the layering protection for massive networks and stored data that ensure the acceptance of rules and regulations as a whole there are three types the first of which is physical security the next being technical and the third being administrative let&#39;s look into physical security first this is the most basic level that includes protecting data and network through unauthorized personnel from acquiring control over the confidentiality of the network these include external peripherals and routers that might be used for cable connections the same can be achieved by using devices like biometric systems physical security is critical especially for small businesses that do not have many resources to devote to security personnel and the tools as opposed to large firms when it comes to technical network security it focuses mostly on safeguarding data either kept in the network or engaged in network transitions this kind fulfills two functions one is depends against unauthorized users the other is a defense against malevolent actions the last category is administrative this level of network security protects user behavior like how the permission has been granted and how the authorization process takes place this also ensures the level of sophistication the network might need to protect it through all the attacks this level also suggests necessary amendments that have to be done to the infrastructure i think that&#39;s all the basics that we need to cover on network security in which our next topic we&#39;re going to go through two mediums of network security which are the transport layer and the application layer the transport layer is a way to secure information as it is carried over the internet with users browsing websites emails instant messaging etc tls aims to provide a private and secure connection between a web browser and a website server it does this with a cryptographic handshake between two systems using public key cryptography the two parties through the connection exchange a secret token and once each machine validates this token it is used for all communications the connection employs lighter symmetric cryptography to save bandwidth and processing power since the application layer is the closest layer to the end user it provides hackers with the largest threat surface poor app layer security can lead to performance and stability issues data theft and in some cases the network being taken down examples of application layer attacks include distributed denial of service attacks or tdos attacks http flats hp injections cross-site scripting etc most organizations have an arsenal of application layer security protections to combat these and more such as web application firewalls secure web gateway services etc now that we have the theory behind network security has been covered in detail let us go through some of the tools that can be used to enforce these network security policies the first two to be covered in the section is a firework a firewall is a type of network security device that keeps track of incoming and outgoing network traffic and it decides which traffic to allow or deny in accordance to a set of security rules for more than 25 years firewalls have served a network security&#39;s first line of defense they provide a barrier between trustworthy internal protected and regulated networks from shady external networks like the internet at some point the next tool which can be used to bolster network security is a virtual private network or vpn for short it&#39;s an encrypted connection between a device and a network via the internet the encryptment connection is the secure transmission of sensitive data it makes it impossible for unauthorized parties to eavesdrop on the traffic and enables remote work for the user the usage of vpn technology is common in both corporate and personal networks next we cover the importance of inclusion prevention systems in network security or ips frameworks an intrusion prevention system is a network security tool that continually scans the network for harmful activity and responds to it when it does occur by reporting blocking or discarding it it can be either hardware or software it&#39;s more sophisticated than an inclusion detection system or an ids framework which can just warn an administrator and merely identify harmful activities while in the case of an ips it actually takes against that activity the next tool in this section and final one are going to be behavioral analytics behavior analytics focus more on the statistics that are being carried over and stored through months and years of usage when some kind of similar pattern is noted that the idea administrator can detect some kind of attack the similar attacks can be stopped and the security can be further enhanced another day i&#39;ve covered all that we need to know about network security the necessary tools it&#39;s different types etc let&#39;s go through the benefits of network security as a whole the first which is protection against external threats the objective for cyber assaults can be as varied as the defenders themselves although they are typically initiated for financial gain whether they are industrial spies hacktivists or cyber criminals these bad actors all have one thing in common which is how quick clever and covert the attacks are getting a strong cyber security posture that considers routine software updates may assist firms in identifying and responding to the abuse techniques tools and the common entry points the next benefit is protection against internal threats the human aspect continues to be the cyber security system&#39;s weakest link insider risk can originate from current or former workers third party vendors or even trusted partners and they can be unintentional careless or downright evil aside from that the rapid expansion of remote work and the personal devices used for business purposes while even iot devices in remote locations can make it easier for these kind of threats to go undetected until it&#39;s too late however by proactively monitoring networks and managing access these dangers may be identified and dealt with before they become expensive disasters the third benefit is increased productivity it is nearly impossible for employees to function when network and personal devices are slowed to a crawl by viruses and other cyber attacks during the operation of website and for the company to run you must significantly minimize violations and the amount of downtime required to fix the breach by implementing various cybersecurity measures such as enhanced firewalls wireless scanning and automatic backups employee identification of possible email phishing schemes suspicious links and other malicious criminal activities can also be aided by education and training another benefit is brand trust and reputation customer retention is one of the most crucial elements in business development customers today place a premium on maintaining brand loyalty through a strong cyber security stance since this is the fastest way to get other businesses back get referrals and sell more tickets overall additionally it helps manufacturers get on the vendor list with bigger companies as a part of the supply chain which is only as strong as its weakest link this opens possibilities for potential future endeavors and development it&#39;s all really the all for the theoretical part of network security after covering so many topics let&#39;s go through a small demonstration to drive home this topic&#39;s importance so one of the first things we&#39;re going to cover is the installation of nmap what are we using right now is actually vmware a re-running an instance of a relax distribution known as parrot security operating system the parrot security os is a debian based linux distribution that is catered more towards ethical hackers and penetration testers the howard is created more is it comes pre-installed with a lot of tools that ethical hackers need including nmap so let&#39;s say you&#39;re using another debian based linux distribution if you want to install nmap you can go with the command of sudo apt which is the package manager install and and just press enter at this point it&#39;s going to ask you for your administrator password because of the sudo command which you have used now this epd will change depending on the distribution let&#39;s say using a distribution that is based on arch linux that will be different if there is some other distribution which is built from scratch the commands will differ but more or less a lot of the distributions the main stream distributions that people use like ubuntu zorinos max mint they are debian bs so you&#39;re just going to be using sudo apt install and map if you give your administrator password here it&#39;s going to see that nmap is smashed manually installed and it is already the newest version at this point if you do not have an app in your distribution it&#39;s going to install the necessary package files if i just use the nmap command you can see some help lines where it basically says what kind of flags you can use what are some of the most common commands the version etc it gives a small sample for the usage of nmap now the first one of the most basic functions of nmap is to identify active hosts on your network and app does this by using a ping scan or sometimes it&#39;s called a ping suite this identifies all of the ip addresses that are currently online without sending any packets to these hosts to run the command we&#39;re just going to go with let me just clear the screen for now another thing you have to do before running nmap just for our ease of use is we&#39;re going to use the sudo suv command this will turn our console into an administrator console so let&#39;s say we want to use some drivers or some external adapters or anything that requires administrative permission we don&#39;t have to use the admin password again and again just going to give it a bit of time for it to recognize okay now that you see uh this dollar sign has changed into a hash symbol which means we now have root access of this console right now of this terminal so what we&#39;re going to do for the pink suite where we have to check existing course is are going to use the command in map minus sp and go with the ip address of the current subnet that you are in which is always going to be minus one uh it&#39;s always going to be 192 and 168.1.1 the 24 bracket so this is going to take some time considering this is going to check all the hosts in this particular subnet the command then returns a list of posts on your network which is this and the total number of assigned ip addresses if you can spot like any ip addresses that you cannot account for in your network or your server you can then add further commands to investigate them further using nmap itself now coming to another feature of nmap which is a very important usage is when scanning posts and mac commands can use server names ip addresses or even ip6 addresses a basic nmap command will produce information about the given host so to run a basic port scan we can just use the nmap command with the ip address of the device or the ip address that we are targeting so for now the host machine that i am using currently has this current ip address if you can see the current id address is 192.168.1.22 as it&#39;s written in the ipv4 address preferred section so now we&#39;re going to try and attack this first machine using nmap on parent security operating system so we&#39;re just going to go with the end map 192 162 and press enter and it&#39;s going to start scanning the host for different services and the ap address that are being run on the system the speed of these scans usually depends on how quick the processor is and also how quickly the two machines can connect with each other but two machines i mean the virtual machine in this case and the machine that is being attacked which is right now the host machine which is running vmware workstation as you can see the core scanning is complete for this particular ip address and you can see the number of ports is mentioned and the services that these posts are used for is also mentioned it says which of these are open for example the 53 tcp port we can see it is closed while some of the other ports are open now one more feature of nmap is the ability to guess the operating system of the ip address that we are attacking for that we need to add one more flag which is going to go with the normal command is n map minus 4 and the regular appearance that we are in the process of attacking let&#39;s give it a few minutes to run the scan and it will try and put a small gas on the operating system that this host might be running this gas might not always be accurate but it puts a small idea and this is much more accurate in the case of actually unix based operating system other than windows based operating systems may be able to detect that if it is a windows a linux macintosh and so on but it may have difficulty finding exact single versions which becomes easier in the case of linux because we can identify different distributions by some of the kernels which and most of the vulnerabilities comes from the kernels and not the particular distributions as you can see the os detection guess is complete and you can see aggressive os is over here which is microsoft windows xp service pack or windows server and there&#39;s the 98 guess that it&#39;s mostly like i mentioned if you can guess if it is a windows based system you can apply the vulnerabilities and exploits accordingly now at times you may need to detect service version and the and similar information from these open ports actually this is useful for troubleshooting and scanning for vulnerabilities or locating services that need to be updated considering a lot of the new updates are used to fix these kind of open vulnerabilities so the flag that we&#39;re going to use in this case is minus sv or hyphen s3 so only this is going to change with the nmap and the ip address of the whole system staying consistent a lot of the services that are being run on these ports are often not the most safe for example apache web server which is a very common web server being used for even local and global projects uh a lot of the older versions used to have systems that can allow privilege escalations or other vulnerabilities that can allow hacker to get into your system without even you getting a trace of it silhouetted versions tend to fix these as quickly as possible and most of these versions do not circulate in the real world but can be used for ethical hacking and testing on how these validate and how these vulnerabilities can be attacked further now with the sv command scan is complete we can see that it is mentioning some of the version of the services that are being run on the particular post once again like i mentioned using these version numbers you can identify particular vulnerabilities and use the exploits design for these vulnerabilities to gain access to the system another thing that nmap does well is port scanning it&#39;s now the basic utilities actually that nmap offers and consequently there are few ways that this command can be customized further for example to come to start a port scan we&#39;re going to use the flag of my ipin p we&#39;re going to specify a random port for example 443 which we know it will be open because it is the port used for https connections which is obviously essential for you to access the internet and once again we are going to use the ip address or local host as the test machine that have been attacked as you can see it clearly states that the four fourth report is open as expected now you can use multiple ports you can check multiple ports this way for example and map and p we&#39;re going to use scan three different ports four four three eighty and four four five address again and it&#39;s going to show the state of all the three ports now you can see this filter part here which which does not mean it is open and it cannot be exploited in any way at least right now maybe there is any other service that is being run it can be exploited further but right now it is in a filtered condition that is how we can actually scan for multiple ports together we can also we can also use actually in a sports car in a range format for example let&#39;s say we&#39;re going to scan the ports from 200 to 300 and once again going to use the hyphen key flag then the ip address of the system being attacked it&#39;s going to scan all the posts from 200 to 300 and mention what are the ports that are open filtered or just straight up closed as you can see all the 101 stand posts are in ignore state for example if we try to scan a range in a more reasonable range for example uh 4 4 3 2 4 6 that&#39;s it we&#39;ll keep the ip address similar and you can see two of them are open and two of them are filtered for different different reasons this is how you can find out which of the ports are liable for exploitation before attacking these kind of devices hope you enjoy this video please let us know in the comments section if you have any issues with network security or the things that you learned in this video subscribe to our channel for more videos like this and thank you for watching [Music] hi there if you like this video subscribe to the simply learn youtube channel and click here to watch similar videos to nerd up and get certified click here

Transcript for:Network Security Lecture Notes

Transcript for:
Network Security Lecture Notes