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CVE-2021-3156
CISA KEV
high
[KEV] Vulnerability in sudo (CVE-2021-3156)
Summary
vulnerability in sudo (CVE-2021-3156). Successful exploitation can lead to full system takeover. Listed in CISA KEV — actively exploited.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2021-3156** has been found in sudo.
Successful exploitation can lead to full system takeover. CVSS score: ?/10.
Note: CISA has officially confirmed this is **actively exploited in the wild**. Treat it with elevated urgency.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "sudo CVE-2021-3156" on the vendor's site.
CVE-2021-3156 (sudo) — CWE-122 /
Attack vector: local / no user interaction
Listed in CISA KEV — actively exploited, treat as top priority.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
❓ What is the problem
**A vulnerability** (CWE-122) exists in sudo.
📍 Affected scope
sudo — .
🔥 Severity
Severity: High. Successful exploitation can lead to full system takeover **Listed in CISA KEV** — actively exploited in the wild, treat as top priority.
🔧 How to fix
Update to the patched release per vendor advisory.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.依存マニフェストで影響コンポーネントを特定する。
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4Consider incident declaration escalate
Notify SOC / on-callCISA KEV登録済 = 実環境で悪用が観測されている。Step 3 で兆候があればインシデント対応宣言、無くてもパッチ適用までWAF強化を最優先で。
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7Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 3 と同じログクエリでアラート再発が無いか継続監視。
References
- advisory NVD
- advisory http://seclists.org/fulldisclosure/2021/Feb/42
- advisory http://www.openwall.com/lists/oss-security/2021/01/27/1
- advisory http://www.openwall.com/lists/oss-security/2021/01/27/2
- advisory https://kc.mcafee.com/corporate/index?page=content&id=SB10348
- advisory https://lists.debian.org/debian-lts-announce/2021/01/msg00022.html
- advisory https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CALA5FTXIQBRRYUA2ZQNJXB6OQMAXEII/
- advisory https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LHXK6ICO5AYLGFK2TAX5MZKUXTUKWOJY/
- advisory https://security.gentoo.org/glsa/202101-33
- advisory https://security.netapp.com/advisory/ntap-20210128-0001/
- advisory https://security.netapp.com/advisory/ntap-20210128-0002/
- advisory https://support.apple.com/kb/HT212177
- advisory https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sudo-privesc-jan2021-qnYQfcM
- advisory https://www.beyondtrust.com/blog/entry/security-advisory-privilege-management-for-unix-linux-pmul-basic-and-privilege-management-for-mac-pmm-affected-by-sudo-vulnerability
- advisory https://www.debian.org/security/2021/dsa-4839
- advisory https://www.kb.cert.org/vuls/id/794544
- advisory https://www.sudo.ws/stable.html#1.9.5p2
- advisory https://www.synology.com/security/advisory/Synology_SA_21_02
- patch http://www.openwall.com/lists/oss-security/2021/09/14/2
- patch https://www.oracle.com//security-alerts/cpujul2021.html
- patch https://www.oracle.com/security-alerts/cpuapr2022.html
- patch https://www.oracle.com/security-alerts/cpuoct2021.html
- report http://packetstormsecurity.com/files/161160/Sudo-Heap-Based-Buffer-Overflow.html
- report http://packetstormsecurity.com/files/161230/Sudo-Buffer-Overflow-Privilege-Escalation.html
- report http://packetstormsecurity.com/files/161270/Sudo-1.9.5p1-Buffer-Overflow-Privilege-Escalation.html
- report http://packetstormsecurity.com/files/161293/Sudo-1.8.31p2-1.9.5p1-Buffer-Overflow.html
- report http://packetstormsecurity.com/files/176932/glibc-syslog-Heap-Based-Buffer-Overflow.html
- report http://seclists.org/fulldisclosure/2021/Jan/79
- report http://seclists.org/fulldisclosure/2024/Feb/3
- report http://www.openwall.com/lists/oss-security/2021/01/26/3
- report http://www.openwall.com/lists/oss-security/2021/02/15/1
- report http://www.openwall.com/lists/oss-security/2024/01/30/6
- report https://www.openwall.com/lists/oss-security/2021/01/26/3
- report https://www.vicarius.io/vsociety/posts/sudoedit-pwned-cve-2021-3156
- web https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3156
- web http://www.openwall.com/lists/oss-security/2024/01/30/8