Home/CVE/An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary undetectable proxy to bypass f
CVE

CVE-2021-20042

An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary undetectable proxy to bypass f

An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary undetectable proxy to bypass firewall rules. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.

CRITICAL · CVSS 9.8 EPSS 0.00559
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-441Unintended Proxy or Intermediary ('Confused Deputy')
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Affected Products & Versions

5
sonicwall sma 200 firmwareall versions
sonicwall sma 210 firmwareall versions
sonicwall sma 410 firmwareall versions
sonicwall sma 400 firmwareall versions
sonicwall sma 500v firmwareall versions
◈

Detection Rules (IDS/IPS)

1
et-openET WEB_SERVER SonicWall SMA Unauthenticated sonicfiles Confused Deputy (CVE-2021-20042)web-application-attack
Open rulesets (ET Open, Snort Community, abuse.ch) link to source. Commercial rulesets are reference-only.
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Scoring & Timeline

9.8
CRITICAL · CVSS v3.1 · PSIRT@sonicwall.com
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 NVD08 Dec 2021 · 10:15 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026Vendor Advisory
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