Description
The openvpn_decrypt function in crypto.c in OpenVPN 2.3.0 and earlier, when running in UDP mode, allows remote attackers to obtain sensitive information via a timing attack involving an HMAC comparison function that does not run in constant time and a padding oracle attack on the CBC mode cipher.
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 | openvpn | 2.3.1-1 | — |
| Debian 13 | openvpn | 2.3.1-1 | — |
| Debian 12 | openvpn | 2.3.1-1 | — |
References
- FEDORA-2013-7552 vendor-advisory
- FEDORA-2013-7531 vendor-advisory
- openSUSE-SU-2013:1645 vendor-advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=960192
- [oss-security] 20130506 Re: CVE request: OpenVPN use of non-constant-time memcmp in HMAC comparison in openvpn_decrypt mailing-list
- MDVSA-2013:167 vendor-advisory
- openSUSE-SU-2013:1649 vendor-advisory
- https://bugs.gentoo.org/show_bug.cgi?id=468756
- https://github.com/OpenVPN/openvpn/commit/11d21349a4e7e38a025849479b36ace7c2eec2ee
- https://community.openvpn.net/openvpn/wiki/SecurityAnnouncement-f375aa67cc