Net-SNMP through 5.7.3 allows Escalation of Privileges because of UNIX symbolic link (symlink) following.
Weakness
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Net-snmp | Net-snmp | * | 5.7.3 (including) |
| Net-snmp | Ubuntu | bionic | * |
| Net-snmp | Ubuntu | devel | * |
| Net-snmp | Ubuntu | esm-infra-legacy/trusty | * |
| Net-snmp | Ubuntu | esm-infra/bionic | * |
| Net-snmp | Ubuntu | esm-infra/focal | * |
| Net-snmp | Ubuntu | esm-infra/xenial | * |
| Net-snmp | Ubuntu | focal | * |
| Net-snmp | Ubuntu | trusty | * |
| Net-snmp | Ubuntu | trusty/esm | * |
| Net-snmp | Ubuntu | upstream | * |
| Net-snmp | Ubuntu | xenial | * |
Potential Mitigations
- Follow the principle of least privilege when assigning access rights to entities in a software system.
- Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/132.html
- https://cwe.mitre.org/data/definitions/17.html
- https://cwe.mitre.org/data/definitions/35.html
- https://cwe.mitre.org/data/definitions/76.html
References
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=966599
- https://github.com/net-snmp/net-snmp/commit/4fd9a450444a434a993bc72f7c3486ccce41f602
- https://github.com/net-snmp/net-snmp/issues/145
- https://security.gentoo.org/glsa/202008-12
- https://security.netapp.com/advisory/ntap-20200904-0001/
- https://usn.ubuntu.com/4471-1/
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=966599
- https://github.com/net-snmp/net-snmp/commit/4fd9a450444a434a993bc72f7c3486ccce41f602
- https://github.com/net-snmp/net-snmp/issues/145
- https://security.gentoo.org/glsa/202008-12
- https://security.netapp.com/advisory/ntap-20200904-0001/
- https://usn.ubuntu.com/4471-1/