CVE-2015-9019

In libxslt 1.1.29 and earlier, the EXSLT math.random function was not initialized with a random seed during startup, which could cause usage of this function to produce predictable outputs.

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://bugzilla.gnome.org/show_bug.cgi?id=758400
• https://bugzilla.suse.com/show_bug.cgi?id=934119