CVE-2021-36369

moderate-risk
Published 2022-10-12

An issue was discovered in Dropbear through 2020.81. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it is possible for an SSH server to change the login process in its favor. This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass. Thus, it allows an attacker to abuse a forwarded agent for logging on to another server unnoticed.

Do I need to act?

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0.14% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

Affected Products (2)

Affected Vendors

Debian Dropbear Ssh Project

References (8)

Third Party Advisory https://github.com/mkj/dropbear/pull/128
Release Notes https://github.com/mkj/dropbear/releases
Release Notes https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82
Mailing List https://lists.debian.org/debian-lts-announce/2022/11/msg00015.html
Third Party Advisory https://github.com/mkj/dropbear/pull/128
Release Notes https://github.com/mkj/dropbear/releases
Release Notes https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82
Mailing List https://lists.debian.org/debian-lts-announce/2022/11/msg00015.html
34
/ 100
moderate-risk
Severity 26/34 · High
Exploitability 1/34 · Minimal
Exposure 7/34 · Low