IT administrators with Ivanti’s Connect Secure/Pulse Secure VPNs and Policy Secure gateways are urged to install mitigations immediately.
The mitigations are to temporarily deal with two vulnerabilities (CVE-2023-46805, an authentication bypass and CVE-2024-21887, a command injection) that impact all supported versions of these products.
If they are chained together, “exploitation does not require authentication and enables a threat actor to craft malicious requests and execute arbitrary commands on the system,” the company said.
“It is critical that you immediately take action to ensure you are fully protected,” the company said in an advisory.
Patches will be released in a staggered schedule, with the first version targeted to be available to customers the week of Jan. 22, with the final version targeted to be available the week of Feb. 19. Until then, the mitigations will have to do.
The vulnerabilities were discovered by researchers at Volexity, who in December detected suspicious lateral movement on the network of one of its network security monitoring service customers. An attacker was placing webshells on the customer’s internal and external-facing web servers. Investigating further, Veloxity found that logs on the customer’s Ivanti Connect Secure VPN had been wiped and logging had been disabled. It then discovered two different zero-day exploits which were being chained together to achieve unauthenticated remote code execution.
“When combined, these two vulnerabilities make it trivial for attackers to run commands on the system,” Volexity says in its report. “In this particular incident, the attacker leveraged these exploits to steal configuration data, modify existing files, download remote files, and reverse tunnel from the … VPN appliance.”
Among other things, the attacker modified legitimate Connect Secure components and made changes to the system to evade the the VPN’s Integrity Checker Tool.
“As organizations continue to improve and harden their defense, attackers are continually looking for ways to bypass them,” the Volexity report says. “Internet-accessible systems, especially critical devices like VPN appliances and firewalls, have once again become a favorite target of attackers. These systems often sit on critical parts of the network, cannot run traditional security software, and typically sit at the perfect place for an attacker to operate.
“Organizations need to make sure they have a strategy in place to be able to monitor activity from these devices and quickly respond if something unexpected occurs.”