The global mobile communication system GSM is a network standard created by the European Telecommunication Standards Institute for the European Union. It is designed to be resistant to hacker attacks by utilizing user authentication with a pre-shared key, challenge-response, and over–the–air encryption. However, there are multiple vulnerabilities that might be used to attack various areas of the network. Instead of GSM identification of only the user, the Universal Subscriber Identity Module provided in UMTS employs a longer authentication key that provides better security and authenticates both the network and the user.
A5/1, A5/2, and A5/3 are three well-known GSM cryptographic algorithms used for security. The first and strongest stream cipher is A5/1, which is used in the EU and the United States rather than the weaker A5/2, which is used in other nations. Both ciphers have flaws. As demonstrated in The Hacker Choice cracking effort in 2007, the A5/2 can be hacked using a ciphertext-only assault and the A5/1 using a rainbow table attack.
There have been numerous assaults and attempts to crack the A5 algorithms since 2000. Karsten Nohl created rainbow tables and discovered a new vector for plain text attacks. He claims that it is simple to crack the GSM network by constructing a complete GSM interceptor using only open source components.
Using software from the freemium site, Nohl was able to intercept voice and text conversations using his old Motorola smartphone by impersonating another user to listen to voice mail, make calls, or send text messages. New wiretapping and eavesdropping attacks took the use of loopholes and poor GSM security to hijack audio input and output, allowing third parties to listen in on a conversation.
To send data on the internet, GSM uses GPRS or General Packet Radio Service. In 2011, the GPRS ciphers were cracked in public.
The most prevalent GPRS ciphers are GEA/1 and GEA/2, which have weaknesses that have been discovered by several researchers who have developed open-source GPRS decode software for sniffing GPRS networks. Some carriers utilize the GEA/0 cipher or unencrypted data traffic protocols, leaving subscribers vulnerable to hacker assaults. Users will be safeguarded by the hardest to break GPRS cipher, GEA/3, which is still in use in more contemporary networks, along with USIM and downgrade assaults. It is advised that you migrate to a more secure 128-bit GEA/4 system.
Even with data protection and encryption using some of the three cipher approaches, it is prone to hacker assaults and user tampering such as spoofing, masking, cloning, and so on. GSM networks that use GEA/4 and other modern encryption methods have become more secure for all users as a result of extensive research, practice, and development of GEA/4 and other modern cipher methods.