The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 1.6.9.5 via the hash() function due to use of a hardcoded fall-back salt. This makes it possible for unauthenticated attackers to generate a valid token across sites running the plugin that have not manually set a salt in the wp-config.php file and access booking information that will allow them to make modifications.
Weakness
The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.
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