An issue was discovered in Tor before 0.2.9.15, 0.3.1.x before 0.3.1.10, and 0.3.2.x before 0.3.2.10. The directory-authority protocol-list subprotocol implementation allows remote attackers to cause a denial of service (NULL pointer dereference and directory-authority crash) via a misformatted relay descriptor that is mishandled during voting.
Weakness
The product dereferences a pointer that it expects to be valid but is NULL.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Tor | Torproject | * | 0.2.9.14 (including) |
| Tor | Torproject | 0.3.1.7 (including) | 0.3.1.9 (including) |
| Tor | Torproject | 0.3.1.1-alpha (including) | 0.3.1.1-alpha (including) |
| Tor | Torproject | 0.3.1.2-alpha (including) | 0.3.1.2-alpha (including) |
| Tor | Torproject | 0.3.1.3-alpha (including) | 0.3.1.3-alpha (including) |
| Tor | Torproject | 0.3.1.4-alpha (including) | 0.3.1.4-alpha (including) |
| Tor | Torproject | 0.3.1.5-alpha (including) | 0.3.1.5-alpha (including) |
| Tor | Torproject | 0.3.1.6-rc (including) | 0.3.1.6-rc (including) |
| Tor | Torproject | 0.3.2.1-alpha (including) | 0.3.2.1-alpha (including) |
| Tor | Torproject | 0.3.2.2-alpha (including) | 0.3.2.2-alpha (including) |
| Tor | Torproject | 0.3.2.3-alpha (including) | 0.3.2.3-alpha (including) |
| Tor | Torproject | 0.3.2.4-alpha (including) | 0.3.2.4-alpha (including) |
| Tor | Torproject | 0.3.2.5-alpha (including) | 0.3.2.5-alpha (including) |
| Tor | Torproject | 0.3.2.6-alpha (including) | 0.3.2.6-alpha (including) |
| Tor | Torproject | 0.3.2.7-rc (including) | 0.3.2.7-rc (including) |
| Tor | Torproject | 0.3.2.8-rc (including) | 0.3.2.8-rc (including) |
| Tor | Torproject | 0.3.2.9 (including) | 0.3.2.9 (including) |
| Tor | Ubuntu | artful | * |
| Tor | Ubuntu | esm-apps/xenial | * |
| Tor | Ubuntu | upstream | * |
| Tor | Ubuntu | xenial | * |
Potential Mitigations
References
- https://blog.torproject.org/new-stable-tor-releases-security-fixes-and-dos-prevention-03210-03110-02915
- https://trac.torproject.org/projects/tor/ticket/25074
- https://www.debian.org/security/2018/dsa-4183
- https://blog.torproject.org/new-stable-tor-releases-security-fixes-and-dos-prevention-03210-03110-02915
- https://trac.torproject.org/projects/tor/ticket/25074
- https://www.debian.org/security/2018/dsa-4183