CVE-2020-9449

An insecure random number generation vulnerability in BlaB! AX, BlaB! AX Pro, BlaB! WS (client), and BlaB! WS Pro (client) version 19.11 allows an attacker (with a guest or user session cookie) to escalate privileges by retrieving the cookie salt value and creating a valid session cookie for an arbitrary user or admin.

Weakness

The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

Affected Software

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.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/112.html
• https://cwe.mitre.org/data/definitions/485.html
• https://cwe.mitre.org/data/definitions/59.html

References

• https://justblab.com/latest-news