Potential recycling of random numbers used in cryptography exists within PuTTY before 0.71.
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 |
|---|---|---|---|
| Putty | Putty | * | 0.71 (excluding) |
| Putty | Ubuntu | bionic | * |
| Putty | Ubuntu | cosmic | * |
| Putty | Ubuntu | esm-apps/xenial | * |
| Putty | Ubuntu | trusty | * |
| Putty | Ubuntu | upstream | * |
| Putty | Ubuntu | xenial | * |
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
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00004.html
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00020.html
- http://www.securityfocus.com/bid/107523
- https://lists.debian.org/debian-lts-announce/2019/04/msg00023.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/36LWQ3NPFIV7DC7TC4KFPRYRH2OR7SZ2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LDO3F267P347E6U2IILFCYW7JPTLCCES/
- https://seclists.org/bugtraq/2019/Apr/6
- https://security.netapp.com/advisory/ntap-20190329-0002/
- https://security.netapp.com/advisory/ntap-20190401-0002/
- https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
- https://www.debian.org/security/2019/dsa-4423
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00004.html
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00020.html
- http://www.securityfocus.com/bid/107523
- https://lists.debian.org/debian-lts-announce/2019/04/msg00023.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/36LWQ3NPFIV7DC7TC4KFPRYRH2OR7SZ2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LDO3F267P347E6U2IILFCYW7JPTLCCES/
- https://seclists.org/bugtraq/2019/Apr/6
- https://security.netapp.com/advisory/ntap-20190329-0002/
- https://security.netapp.com/advisory/ntap-20190401-0002/
- https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
- https://www.debian.org/security/2019/dsa-4423