{"id":"CVE-2021-20039","published":"2021-12-08T09:55:21Z","modified":"2025-09-05T17:09:47Z","title":"Improper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method…","vendor":"SonicWall","product":"SonicWall SMA100","tier":"core","eol":null,"affectedVersions":[{"vendor":"SonicWall","product":"SonicWall SMA100","versions":["9.0.0.11-31sv and earlier","10.2.0.8-37sv and earlier","10.2.1.1-19sv and earlier","10.2.1.2-24sv and earlier"]}],"description":{"text":"Improper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.","provenance":"source","from":"CVE.org"},"summary":{"text":"The SonicWall SMA100 management interface, specifically the '/cgi-bin/viewcert' endpoint handling POST requests, fails to properly neutralize special elements, creating an OS command injection flaw. A remote attacker with low-privilege authenticated access to the network can inject arbitrary commands that run as the 'nobody' user, with no user interaction required; the flaw affected SMA 200, 210, 400, 410 and 500v appliances.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-31T05:10:09Z"},"cvss":{"score":8.8,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"CISA ADP Vulnrichment"},"epss":{"score":0.78746,"percentile":0.9959,"date":"2026-10-30","provenance":"source"},"kev":null,"vulncheckKev":{"dateAdded":"2024-03-30","exploitedFirstSeen":"2024-03-30","ransomware":false,"evidence":[{"url":"https://dfir.ch/posts/microsocks_sonicwall/","date":"2024-03-30"},{"url":"https://cloud.google.com/blog/topics/threat-intelligence/sonicwall-secure-mobile-access-exploitation-overstep-backdoor","date":"2025-07-16"},{"url":"https://fortiguard.fortinet.com/outbreak-alert/sonicwall-sma-attack","date":"2025-07-18"}],"evidenceTotal":3,"provenance":"source"},"exploited":true,"otx":{"pulseCount":6,"pulses":[{"name":"IOC - Ongoing SonicWall Secure Mobile Access (SMA) Exploitation Campaign using the OVERSTEP Backdoor","url":"https://otx.alienvault.com/pulse/687dfdc0ecabb585722195d6","created":"2025-07-21"},{"name":"Ongoing SonicWall Secure Mobile Access (SMA) Exploitation Campaign using the OVERSTEP Backdoor","url":"https://otx.alienvault.com/pulse/687df4963b1a8715eb3b4b93","created":"2025-07-21"},{"name":"Ongoing SonicWall Secure Mobile Access (SMA) Exploitation Campaign using the OVERSTEP Backdoor.","url":"https://otx.alienvault.com/pulse/687c14745277acd279334e8c","created":"2025-07-19"},{"name":"Ongoing SonicWall Secure Mobile Access (SMA) Exploitation Campaign using the OVERSTEP Backdoor | Google Cloud Blog","url":"https://otx.alienvault.com/pulse/6878c2eb16c8bcb5d7b1e566","created":"2025-07-17"},{"name":"Thor-Lite Linux 64 (06.11.24) - enriched a bit more but not 'pruned'","url":"https://otx.alienvault.com/pulse/6668b85065eec626e4766a38","created":"2024-06-11"},{"name":"Proof Point Emerging Exploit list","url":"https://otx.alienvault.com/pulse/6399fdc966948f6b537b9762","created":"2022-12-14"}],"provenance":"machine"},"cwes":[{"id":"CWE-78","name":"Improper Neutralization of Special Elements used in an OS Command"}],"references":[{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026","tags":["x_refsource_CONFIRM"]},{"url":"http://packetstormsecurity.com/files/165563/SonicWall-SMA-100-Series-Authenticated-Command-Injection.html","tags":["x_refsource_MISC"]},{"url":"https://attackerkb.com/topics/9szJhq46lw/cve-2021-20039/rapid7-analysis","tags":["exploit"]}],"techniques":[],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-7502","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-7502","exploited":false,"exploitedSince":null,"provenance":"source"},"exploits":[],"exploitSources":{"metasploit":[{"name":"SonicWall SMA 100 Series Authenticated Command Injection","module":"exploit/linux/http/sonicwall_cve_2021_20039","type":"exploit","disclosureDate":"2021-12-14","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/http/sonicwall_cve_2021_20039.rb"}],"first":{"date":"2021-12-14","source":"Metasploit","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/http/sonicwall_cve_2021_20039.rb"},"provenance":"source"},"exploitRefs":["https://attackerkb.com/topics/9szJhq46lw/cve-2021-20039/rapid7-analysis","http://packetstormsecurity.com/files/165563/SonicWall-SMA-100-Series-Authenticated-Command-Injection.html"],"flow":[],"timeline":[{"date":"2021-12-08","kind":"published","label":"Published (CVE.org)","url":"https://www.cve.org/CVERecord?id=CVE-2021-20039","provenance":"source"},{"date":"2021-12-14","kind":"exploit-public","label":"First public exploit: Metasploit","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/http/sonicwall_cve_2021_20039.rb","provenance":"source"},{"date":"2024-03-30","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://dfir.ch/posts/microsocks_sonicwall/","provenance":"source"}],"speed":{"daysToPublicExploit":6,"firstExploitFrom":"Metasploit","daysToKev":null},"priority":{"score":68.0,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 945 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.92,"detail":"percentile 0.9959"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 NVD reference tagged Exploit; 1 NVD exploit link; 1 Metasploit module"},{"name":"Mentioned in OTX pulses","points":1.92,"detail":"6 pulses"},{"name":"CVSS severity","points":6.16,"detail":"base score 8.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}