CVE-2021-21352

Anuko Time Tracker is an open source, web-based time tracking application written in PHP. In TimeTracker before version 1.19.24.5415 tokens used in password reset feature in Time Tracker are based on system time and, therefore, are predictable. This opens a window for brute force attacks to guess user tokens and, once successful, change user passwords, including that of a system administrator. This vulnerability is pathced in version 1.19.24.5415 (started to use more secure tokens) with an additional improvement in 1.19.24.5416 (limited an available window for brute force token guessing).

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://github.com/anuko/timetracker/commit/40f3d9345adc20e6f28eb9f59e2489aff87fecf5
• https://github.com/anuko/timetracker/security/advisories/GHSA-43c9-rx4h-4gqq
• https://www.anuko.com/time-tracker/index.htm