Home/CVE/An issue was discovered in Dropbear through 2020.81. Due to a non-RFC-compliant check of the available authentication me
CVE

CVE-2021-36369

An issue was discovered in Dropbear through 2020.81. Due to a non-RFC-compliant check of the available authentication me

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.

HIGH · CVSS 7.5 EPSS 0.0021
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-287Improper Authentication
CWE-287Improper Authentication
▤

Affected Products & Versions

2
dropbear ssh project dropbear ssh<= 2020.81
debian linuxall versions
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD12 Oct 2022 · 09:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

3
usnUSN-7292-1
siemens-csafSSA-806742
cisa-csafcisa-csaf-csaf_files-OT-white-2024-icsa-24-046-11
🔗

References & Sources

4
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/mkj/dropbear/pull/128Third Party Advisory
https://github.com/mkj/dropbear/releasesRelease NotesThird Party Advisory
https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82Release NotesThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/11/msg00015.htmlMailing ListThird Party Advisory
Intelligence Graph · click any node to traverse
CVETechnique ActorTool Family
drag to reposition · click any node to traverse · button top-right enlarges
External lookups - second-class, for what we don’t hold ourselves
NVDCVE.orgCISAVulnersExploit-DBGitHub PoCVulnCheck KEVGreyNoise
Vulnerabilities
CISA KEV catalog
CWE weaknesses
CAPEC attack patterns
Package vulnerabilities
Threat intelligence
Threat actors
Tools & malware
ATT&CK techniques
IOCs
Detection & defense
Sigma rules
YARA rules
Atomic Red Team tests
D3FEND countermeasures
Compliance
NIST 800-53
ISO 27001:2022
SOC 2 TSC
PCI-DSS v4.0
CIS Controls v8.1
About
All capabilities
Live statistics
Data sources
Privacy policy
Terms of service
threatengine.sh  ·  Open-source threat intelligence platform  ·  100+ authoritative sources  ·  Every fact traces to its origin