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SonicWall Patches Critical Vulnerability in SMA Appliances

SonicWall has published a security advisory and a security notice to inform customers about a critical vulnerability affecting some of its Secure Mobile Access (SMA) appliances.

The flaw, identified as CVE-2021-20034, can be exploited by a remote, unauthenticated attacker to delete arbitrary files from the targeted appliance, which could result in the device being reset to factory settings. The security hole can also allow an attacker to gain administrator access to the underlying host.

The cybersecurity firm highlighted that it has seen no evidence of the vulnerability being exploited in the wild. It’s not surprising that this statement is highlighted in the vendor’s advisory considering that SMA appliances have been known to be targeted by malicious actors, in some cases even before a patch was released.

CVE-2021-20034 was reported to SonicWall by Wenxu Yin, a researcher at Chinese cybersecurity firm Qihoo 360.

The vulnerability has been found to impact SMA 200, 210, 400, 410 and 500v appliances running versions 10.2.1.0-17sv, 10.2.0.7-34sv and 9.0.0.10-28sv, and earlier. Patches have been released for each of the affected versions.

“The vulnerability (SNWLID-2021-0021) is due to an improper limitation of a file path to a restricted directory potentially leading to arbitrary file deletion as ‘nobody’,” SonicWall explained in its security notice.

The latest updates for SMA 100 series appliances also patch two medium-severity vulnerabilities, including one that can lead to privilege escalation to root, and one that can be exploited for authenticated arbitrary code injection and DoS attacks.

SonicWall says it has more than half a million customers in over 215 countries and territories so it’s not surprising that its products have been targeted by malicious hackers.

Alerts issued earlier this year warned of threat actors exploiting both old and new vulnerabilities, including in SMA, Secure Remote Access (SRA), and Email Security products.

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Related: SonicWall Zero-Day Exploited by Ransomware Group Before It Was Patched

Related: Researcher Describes Potential Impact of Recently Patched SonicWall NSM Flaw

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.