CVE-2021-20038
Exploited in the wild. In CISA KEV since 2022‑01‑28. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module environment variables allows a remote unauthenticated attacker to potentially execute code as a 'nobody' user in the appliance. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances firmware 10.2.0.8-37sv, 10.2.1.1-19sv, 10.2.1.2-24sv and earlier versions.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Listed as exploited in the wild since 2022-01-28.
US federal agencies must remediate by 2022-02-11.
Known use in ransomware campaigns.
Apply updates per vendor instructions.
- Public exploits
2 sources with a proof of concept or module.
Exploit links, PoCs and Metasploit modules after sign-in- EPSS
100% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
The patch came 126 days before any public exploit.
- OpenVAS check added
- Public exploit / PoCsource: github-pocnuclei check added
- Patch availablerecord updated
- Added to CISA KEVransomware campaign
- Publishedweakness classified, att&ck mapped
Affected products
And 4 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Scored 9.8 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
- Initial AccessT1190Exploit Public-Facing Applicationhigh confidence
- Privilege EscalationT1068Exploitation for Privilege Escalationhigh confidence
Sources
References in the record
- nvd.nist.gov/vuln/detail/CVE-2021-20038&
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026
- github.com/jbaines-r7/badblood
And 3 more references. See all after sign-in
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We'll flag the next CVE, public exploit or patch for SMA 100, not every advisory. This one: actively exploited.
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