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More than 25,000 SonicWall SSL VPN devices are vulnerable to critical flaws, with 20,000 running outdated SonicOS/OSX firmware that is no longer supported.
This analysis by cybersecurity firm Bishop Fox was prompted by key vulnerabilities disclosed this year in SonicWall devices. Ransomware groups, like Fog and Akira, have recently exploited vulnerabilities in SonicWall SSL VPN devices to gain initial access to corporate networks.
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Bishop Fox used internet scanning tools like Shodan and BinaryEdge to find 430,363 publicly exposed SonicWall firewalls.
Public exposure means that the firewall’s management or SSL VPN interfaces are reachable from the internet, allowing attackers to look for vulnerabilities, outdated firmware, misconfigurations, and weak passwords.
“The management interface on a firewall should never be publicly exposed, as this presents an unnecessary risk,” explains BishopFox.
“The SSL VPN interface, although designed to provide access to external clients over the internet, should ideally be protected by source IP address restrictions.”
Researchers found that 6,633 devices use outdated Series 4 and 5 firmware, which are no longer supported, while 14,077 devices run unsupported versions of the partially supported Series 6.
This means that 20,710 devices with outdated firmware are vulnerable to various public exploits, but this number does not reflect the true extent of the issue.
BishopFox identified 13,827 devices with unknown firmware, 197,099 devices with unsupported Series 6 firmware without exact version details, and 29,254 devices with unknown Series 5 firmware.
The scan results revealed that 25,485 firmware versions are vulnerable to critical issues, while 94,018 are at risk from high-severity flaws. Many vulnerable devices are running Series 7 firmware and haven’t been updated to the latest version that fixes security issues.
The current total of 119,503 vulnerable endpoints shows improvement from 178,000 vulnerable to DoS and RCE attacks in January 2024, but it still reflects a slow adoption of patches.
