FortiOS flaw was exploited to compromise governmental targets (CVE-2022-42475)
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2022-42475 | Unauthenticated Heap Overflow in Fortinet FortiOS/FortiProxy SSL-VPN (Critical RCE) CVE-2022-42475 is a critical (CVSS 9.8) heap-based buffer overflow in the SSL-VPN service of Fortinet FortiOS and FortiProxy. A remote, unauthenticated attacker can trigger it by sending specifically crafted requests to an exposed SSL-VPN interface, with no user interaction or credentials required. Successful exploitation yields arbitrary code or command execution on the appliance, giving attackers a foothold on the perimeter device from which they can pivot into internal networks. Any organization running the listed FortiOS (6.0 through 7.2) or FortiProxy (7.0/7.2) versions with SSL-VPN enabled is affected. Exploitation is confirmed in the wild: the flaw is in CISA KEV with known ransomware use, has near-certain exploitation probability (EPSS 99.5%), and has been used in targeted government attacks and a Chinese-nexus espionage campaign that compromised over 20,000 systems, with attackers also noted to retain access even after patching. Do: Upgrade FortiOS and FortiProxy to fixed releases per Fortinet advisory FG-IR-22-398 (any version beyond the listed affected ranges), and reboot the appliance after patching to clear lingering SSL-VPN sessions since attackers have been observed retaining access post-patch. Check for indicators of compromise such as unknown local accounts, unexpected processes, and anomalous historical logins, and rotate SSL-VPN credentials if compromise is suspected. If SSL-VPN is not required, disable it or restrict exposure to trusted sources until patched. | 9.8 | 99% | KEV ransomware PoC |
| masshundreds of thousands of internet-exposed FortiGate/FortiProxy SSL-VPN endpoints (well over 100,000; 20,000+ confirmed victims in a single campaign) |
Full article307 words · extracted from helpnetsecurity.com · click to collapse
A critical vulnerability in FortiOS SSL-VPN (CVE-2022-42475) that Fortinet has issued patches for in November 2022 has been exploited by attackers to compromise governmental or government-related targets, the company has shared.
Fortinet says the attackers have advanced capabilities: they were able to reverse-engineer various parts of FortiOS to help them with the creation of the exploit, and use a Linux-based implant that was custom-made to run on that operating system.
They also pointed out that the malware can manipulate log files so it can avoid detection. “It searches for elog files, which are logs of events in FortiOS. After decompressing them in memory, it searches for a string the attacker specifies, deletes it, and reconstructs the logs. The malware can also kill the logging processes,” the company explained.
They’ve shared indicators of compromise (IoCs) and detailed how to use them, and have released a signature for intrustion prevention systems (IPS) customers can use to protect themselves.
Defenders want crucial information at the right time
This latest Fortinet disclosure has again pushed into the spotlight the fact that, when some of the FortiOS updates were released in November 2022, there was no indication in the change logs of a vulnerability exploited in the wild having been fixed. The CVE-numbered flaw was added to the change log later but, again, with no indication of its exploitation.
As some of those in charge of patching organizations’ IT and IT Sec solutions have pointed out, a CVE in the change log would have affected their decision to schedule the update sooner rather than later.
As an alternative to implementing the fixes, Fortinet also did not immediately offer a possible workaround (disabling the SSL-VPN functionality).
While they are not the only company to make these kinds of missteps, they should be avoided by all in the future.
Text extracted automatically; images, tables and formatting may be missing. Original: https://www.helpnetsecurity.com/2023/01/13/cve-2022-42475-exploited/