RCE in Sophos Firewall is being exploited in the wild (CVE-2022-3236)

Sophos has patched an actively exploited remote code execution vulnerability (CVE-2022-3236) in its Firewall solutions, and has pushed the fix to customers who have automatic installation of hotfixes enabled.

If this news triggers a feeling of déjà vu, there’s a good reason: earlier this year, another zero-day (CVE-2022-1040) in the same component was leveraged by attackers against “a small set of specific organizations, primarily in the South Asia region” – and this time around is the same.

About CVE-2022-3236

CVE-2022-3236 is a code injection vulnerability in the User Portal and Webadmin of Sophos Firewall. If successfully exploited, it allows for remote code execution (RCE) on the targeted vulnerable installation.

It affects Sophos Firewall v19.0 MR1 (19.0.1) and older. Sophos published hotfixes for a variety of them, and has included the fix in v18.5 MR5 (18.5.5), v19.0 MR2 (19.0.2), and v19.5 GA.

The hotfixes have been pushed to customers with the “Allow automatic installation of hotfixes” feature enabled on remediated versions (the feature is enabled by default).

Customers who don’t have the featured enabled are advised to get the hotfix or to upgrade to a newer version. If none of that is possible, they can protect themselves from external attackers by disabling WAN access to the User Portal and Webadmin. As an alternative for remote access and management, they can use VPN and/or the Sophos Central cloud management platform.

“Users of older versions of Sophos Firewall are required to upgrade to receive the latest protections, and this fix,” the company said.

What about the attacks?

CVE-2022-3236 has been added to CISA’s Known Exploited Vulnerabilities Catalog, which means that US federal civilian executive branch agencies are required to remediate it.

Sophos did not name the organizations that have been compromised by attackers via CVE-2022-3236, but said that they “informed each of these organizations directly.”

According to Volexity researchers, CVE-2022-1040 was used by a Chinese APT group dubbed “Drifting Cloud” in early March 2022.

“DriftingCloud is an effective, well equipped, and persistent threat actor targeting five-poisons-related targets. They are able to develop or purchase zero-day exploits to achieve their goals, tipping the scales in their favor when it comes to gaining entry to target networks,” the researchers noted.

Vulnerabilities in Sophos firewalls are often exploited by attackers.