CVE-2021-20038
Published on December 8, 2021
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.
Known Exploited Vulnerability
This SonicWall SMA 100 Appliances Stack-Based Buffer Overflow Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. SonicWall SMA 100 devies are vulnerable to an unauthenticated stack-based buffer overflow vulnerability where exploitation can result in code execution.
The following remediation steps are recommended / required by February 11, 2022: Apply updates per vendor instructions.
Vulnerability Analysis
CVE-2021-20038 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors in an automatable fashion. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
What is a Stack Overflow Vulnerability?
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
CVE-2021-20038 has been classified to as a Stack Overflow vulnerability or weakness.
Affected Versions
SonicWall SMA100:- Version 10.2.0.8-37sv and earlier is affected.
- Version 10.2.1.1-19sv and earlier is affected.
- Version 10.2.1.2-24sv and earlier is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.