Description
The mm_newkeys_from_blob function in monitor_wrap.c in sshd in OpenSSH 6.2 and 6.3, when an AES-GCM cipher is used, does not properly initialize memory for a MAC context data structure, which allows remote authenticated users to bypass intended ForceCommand and login-shell restrictions via packet data that provides a crafted callback address.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | openssh | 1:6.4p1-1 | — |
| Debian 13 | openssh | 1:6.4p1-1 | — |
| Debian 12 | openssh | 1:6.4p1-1 | — |
References
- http://www.openssh.com/txt/gcmrekey.adv
- [oss-security] 20131107 Re: CVE Request - OpenSSH mailing-list
- HPSBUX03188 vendor-advisory
- openSUSE-SU-2013:1726 vendor-advisory
- USN-2014-1 vendor-advisory