| Name |
Cryptanalysis of Cellular Encryption |
|
| Likelyhood of attack |
Typical severity |
| Medium |
High |
|
| Summary |
The use of cryptanalytic techniques to derive cryptographic keys or otherwise effectively defeat cellular encryption to reveal traffic content. Some cellular encryption algorithms such as A5/1 and A5/2 (specified for GSM use) are known to be vulnerable to such attacks and commercial tools are available to execute these attacks and decrypt mobile phone conversations in real-time. Newer encryption algorithms in use by UMTS and LTE are stronger and currently believed to be less vulnerable to these types of attacks. Note, however, that an attacker with a Cellular Rogue Base Station can force the use of weak cellular encryption even by newer mobile devices. |
| Prerequisites |
None |
| Solutions | Use of hardened baseband firmware on retransmission device to detect and prevent the use of weak cellular encryption. Monitor cellular RF interface to detect the usage of weaker-than-expected cellular encryption. |
| Related Weaknesses |
|
CWE ID
|
Description
|
| CWE-327 |
Use of a Broken or Risky Cryptographic Algorithm |
|
| Related CAPECS |
|
CAPEC ID
|
Description
|
| CAPEC-97 |
Cryptanalysis is a process of finding weaknesses in cryptographic algorithms and using these weaknesses to decipher the ciphertext without knowing the secret key (instance deduction). Sometimes the weakness is not in the cryptographic algorithm itself, but rather in how it is applied that makes cryptanalysis successful. An attacker may have other goals as well, such as: Total Break (finding the secret key), Global Deduction (finding a functionally equivalent algorithm for encryption and decryption that does not require knowledge of the secret key), Information Deduction (gaining some information about plaintexts or ciphertexts that was not previously known) and Distinguishing Algorithm (the attacker has the ability to distinguish the output of the encryption (ciphertext) from a random permutation of bits). |
|