A flaw was found in Avahi-daemon, which relies on fixed source ports for wide-area DNS queries. This issue simplifies attacks where malicious DNS responses are injected.
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 |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | RedHat | avahi-0:0.9~rc2-1.el10_0.1 | * |
| Red Hat Enterprise Linux 9 | RedHat | avahi-0:0.8-22.el9_6.1 | * |
| Red Hat Enterprise Linux 9 | RedHat | avahi-0:0.8-22.el9_6.1 | * |
| Avahi | Ubuntu | focal | * |
| Avahi | Ubuntu | oracular | * |
| Avahi | Ubuntu | plucky | * |
| Avahi | Ubuntu | trusty/esm | * |
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