CVE-2021-36369
This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.46%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- EPSS
- 1.46% probability · 72th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-287
- Affected
- dropbear ssh project/dropbear ssh · debian/debian linux
- Source
- cve@mitre.org
References
- https://github.com/mkj/dropbear/pull/128Third Party Advisory
- https://github.com/mkj/dropbear/releasesRelease Notes, Third Party Advisory
- https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82Release Notes, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/11/msg00015.htmlMailing List, Third Party Advisory
- https://github.com/mkj/dropbear/pull/128Third Party Advisory
- https://github.com/mkj/dropbear/releasesRelease Notes, Third Party Advisory
- https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82Release Notes, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/11/msg00015.htmlMailing List, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.