It’s time to patch your SonicWall SMA 100 series appliances again!

SonicWall has fixed a handful of vulnerabilities affecting its SMA 100 series appliances and is urging organizations to implement the patches as soon as possible.

SonicWall SMA vulnerabilities

Although there’s currently no evidence of these bugs being exploited in active attacks, threat actors have been known to target these appliances in the past by leveraging known and zero-day vulnerabilities.

About the vulnerabilities

The patched vulnerabilities, which were reported by Jake Baines of Rapid7 and Richard Warren of NCC Group received incremental identifiers from CVE-2021-20038 up to CVE-2021-20045.

“The most severe of these flaws are a set of unauthenticated heap- and stack-based buffer overflow vulnerabilities,” notes Claire Tills, senior research engineer at Tenable.

“CVE-2021-20038 covers a single vulnerability and received a CVSSv3 score of 9.8, while CVE-2021-20045 covers multiple vulnerabilities, the bundle received at CVSSv3 score of 9.4. CVE-2021-20038 is the result of using strcat() function when handling environment variables from the HTTP GET method used in the SMA SSLVPN Apache httpd server. CVE-2021-20043 is also a heap-based buffer overflow and it received a CVSSv3 score of 8.8, but it requires authentication to exploit. For all three of these CVEs, successful exploitation would result in code execution as the ‘nobody’ user in the SMA100 appliance.”

More specific details about the flaws have been made available by SonicWall’s PSIRT.

The vulnerabilities affect the whole SMA (Secure Mobile Access) 100 series, i.e., SMA 200, 210, 400, 410 and 500v appliances (both physical and virtual) running various firmware versions. SMA 100 series appliances with WAF enabled are also impacted by the majority of these vulnerabilities.

Organizations are advised to upgrade to firmware version or, and the company also urges users who still use firmware versions 9.0.0.x to upgrade to newer versions, because the former is no longer supported.

UPDATE (January 12, 2022, 01:05 a.m. PT):

Rapid7 researcher Jake Baines has shared the vulnerabilities’ technical details.

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