GoogleOSV:GHSA-RV6R-3F5Q-9RGXTwisted SSH client and server deny of service during SSH handshake.
EPSS
Percentile
75.8%
Impact
The Twisted SSH client and server implementation naively accepted an infinite amount of data for the peer’s SSH version identifier.
A malicious peer can trivially craft a request that uses all available memory and crash the server, resulting in denial of service. The attack is as simple as nc -rv localhost 22 < /dev/zero.
Patches
The issue was fix in GitHub commit https://github.com/twisted/twisted/commit/98387b39e9f0b21462f6abc7a1325dc370fcdeb1
A fix is available in Twisted 22.2.0.
Workarounds
- Limit access to the SSH server only to trusted source IP addresses.
- Connect over SSH only to trusted destination IP addresses.
References
Reported at https://twistedmatrix.com/trac/ticket/10284
Discussions at https://github.com/twisted/twisted/security/advisories/GHSA-rv6r-3f5q-9rgx
For more information
Found by vin01
References
github.com/twisted/twisted
github.com/twisted/twisted/commit/98387b39e9f0b21462f6abc7a1325dc370fcdeb1
github.com/twisted/twisted/releases/tag/twisted-22.2.0
github.com/twisted/twisted/security/advisories/GHSA-rv6r-3f5q-9rgx
lists.debian.org/debian-lts-announce/2022/03/msg00009.html
lists.fedoraproject.org/archives/list/[email protected]/message/7U6KYDTOLPICAVSR34G2WRYLFBD2YW5K
lists.fedoraproject.org/archives/list/[email protected]/message/GLKHA6WREIVAMBQD7KKWYHPHGGNKMAG6
nvd.nist.gov/vuln/detail/CVE-2022-21716
security.gentoo.org/glsa/202301-02
twistedmatrix.com/trac/ticket/10284
www.oracle.com/security-alerts/cpuapr2022.html
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