Critical SonicWall VPN Portal Bug Allows DoS, Worming RCE


Level 75
Content Creator
Malware Hunter
Aug 17, 2014
A critical security bug in the SonicWall VPN portal can be used to crash the device and prevent users from connecting to corporate resources. It could also open the door to remote code execution (RCE), researchers said.

The flaw (CVE-2020-5135) is a stack-based buffer overflow in the SonicWall Network Security Appliance (NSA). According to the researchers at Tripwire who discovered it, the flaw exists within the HTTP/HTTPS service used for product management and SSL VPN remote access.

An unskilled attacker could trigger a persistent denial-of-service condition using an unauthenticated HTTP request involving a custom protocol handler, wrote Craig Young, a computer security researcher with Tripwire’s Vulnerability and Exposures Research Team (VERT), in a Tuesday analysis. But the damage could go further.

“VPN bugs are tremendously dangerous for a bunch of reasons,” he told Threatpost. “These systems expose entry points into sensitive networks and there is very little in the way of security introspection tools for system admins to recognize when a breach has occurred. Attackers can breach a VPN and then spend months mapping out a target network before deploying ransomware or making extortion demands.”
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