Multiple W&T products of the Comserver Series use a small number space for allocating sessions ids. After login of an user an unathenticated remote attacker can brute force the users session id and get access to his account on the the device. As the user needs to log in for the attack to be successful a user interaction is required.
Weakness
The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| At-modem-emulator_firmware |
Wut |
* |
1.48 (excluding) |
Potential Mitigations
- Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds.
- In general, if a pseudo-random number generator is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts.
- Pseudo-random number generators can produce predictable numbers if the generator is known and the seed can be guessed. A 256-bit seed is a good starting point for producing a “random enough” number.
References