Lecture Notes: Hacking Phone Networks

Introduction

• Linus from Linus Tech Tips discusses hacking phone networks.
• Intercepted phone calls and two-factor authentication codes.
• Highlighted how it can happen to anyone.

Historical Context

Blue Box Invention by Jobs and Wozniak

• Jobs and Wozniak's first startup was illegal: creating a blue box to hack phone networks.
• Long-distance calls in the 1970s were extremely expensive.
• Blue box allowed free calls by tricking telephone companies.
• Example: called the Pope pretending to be Henry Kissinger.

Evolution of Phone Systems

• Most phones until the 1920s had no dialing capability.
• Operators manually connected calls; labor-intensive process.
• Automation led to rotary dial telephones and then touch-tone phones in the 1960s.

Touch-Tone and Control Signals

• Touch-tone phones sent frequencies for connection, enabling long-distance automation.
• Vulnerability in the signaling system was exploited by Jobs and Wozniak.
• Used 2600 Hertz tone to disconnect and connect calls for free.
• Resulted in the development of SS7 (Signaling System no. 7) to improve security.

SS7 Vulnerabilities

• SS7 allows mobile networks to communicate but has security risks.
• Used in various attacks, including tracking and intercepting calls/messages.

Case Study: Princess Latifa

• Latifa Al Maktoum claims her father confined her; she attempted to escape.
• SS7 attack was used to locate her yacht using her captain's phone.

Steps to Exploit SS7

Step 1: Infiltrate SS7

• SS7 became vulnerable due to increased number of operators and companies.
• Access costs a few thousand dollars per month.

Step 2: Gain Trust

• Requires collecting the IMSI (International Mobile Subscriber Identity) number.
• IMSI is unique to each SIM card and crucial for attacks.

Step 3: Execute the Attack

• Example demonstration involving Linus's phone calls.
• Phone calls routed to the attackers instead of the intended recipient.

Implications of SS7 Vulnerabilities

• Attacks can include intercepting text messages and two-factor authentication codes.
• The implications for personal security are significant.
• SMS two-factor authentication is not secure enough.

Alternative Security Measures

• Use Authenticator apps or hardware tokens instead of SMS.
• Consider encrypted calling services like Signal or WhatsApp.

Conclusion

• SS7 vulnerabilities pose a serious threat to personal privacy and security.
• Importance of being proactive about personal data security.
• Continuous education in technology and security is vital to stay protected.

Additional Resources

• Brilliant.org for learning about technology and problem-solving skills.