GoogleOSV:GHSA-RV6R-3F5Q-9RGXTwisted SSH client and server deny of service during SSH handshake.
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
0.004 Low
EPSS
Percentile
72.8%
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
Related
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
0.004 Low
EPSS
Percentile
72.8%