Auth bypass in Dropbear SSH Project
CVE-2021-36369
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.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.015 (73.1th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 73rd percentile — 73.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.015 · newest: 0.015 · change: +0.000
Affected products
- Dropbear SSH Project
- Debian Linux — versions 10.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/mkj/dropbear/pull/128 (Third Party Advisory)
- github.com/mkj/dropbear/releases (Third Party Advisory, Release Notes)
- github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82 (Third Party Advisory, Release Notes)
- lists.debian.org/debian-lts-announce/2022/11/msg00015.html (mailing-list, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-36369?
- CVE-2021-36369 is a high-severity vulnerability in Dropbear SSH Project, classified under Improper Authentication. CVSS score: 7.5/10. Published 2022-10-12.
- How severe is CVE-2021-36369?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2021-36369 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.