Researchers from Bishop Fox found over 178,000 SonicWall next-generation firewalls (NGFW) publicly exploitable.
SonicWall next-generation firewall (NGFW) series 6 and 7 devices are affected by two unauthenticated denial-of-service vulnerabilities, tracked as CVE-2022-22274 and CVE-2023-0656, that could potentially lead to remote code execution. Despite a proof-of-concept exploit for the flaw CVE-2023-0656 was publicly released, the vendor is not aware of attack in the wild exploiting the vulnerabilities.
Researchers from Bishop Fox used BinaryEdge source data to find SonicWall firewalls with management interfaces exposed to the internet. The experts found that 76% (178,637 of 233,984) of the Internet-facing firewalls are vulnerable to one or both issues.
The experts pointed out that the two issues are fundamentally the same, but exploitable at different HTTP URI paths due to the reuse of a vulnerable code pattern. The researchers also developed a test script to determine whether a device is vulnerable without crashing it.
This means that the impact of a large-scale attack could be severe.
“In its default configuration, SonicOS restarts after a crash, but after three crashes in a short period of time it boots into maintenance mode and requires administrative action to restore normal functionality.” reads the advisory published by Bishop Fox. “The latest available firmware protects against both vulnerabilities, so be sure to upgrade immediately (and make sure the management interface isn’t exposed to the internet).”
Researchers recommend administrators of vulnerable devices remove the web management interface from public access and upgrade the firmware to the latest available version.
“At this point in time, an attacker can easily cause a denial of service using this exploit, but as SonicWall noted in its advisories, a potential for remote code execution exists. While it may be possible to devise an exploit that can execute arbitrary commands, additional research is needed to overcome several challenges, including PIE, ASLR, and stack canaries.” concludes the report. “Perhaps a bigger challenge for an attacker is determining in advance what firmware and hardware versions a particular target is using, as the exploit must be tailored to these parameters. Since no technique is currently known for remotely fingerprinting SonicWall firewalls, the likelihood of attackers leveraging RCE is, in our estimation, still low.”
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