Ravie LakshmananJul 21, 2026Vulnerability / Network Security
Threat actors have been observed exploiting a now-patched high-severity Palo Alto Networks PAN-OS vulnerability as an entry point to deploy Qilin (aka Agenda) ransomware on victim environments.
Arctic Wolf Labs said it investigated multiple intrusions in June 2026 that began with the exploitation of CVE-2026-0257 (CVSS score: 7.8), an authentication bypass flaw affecting the portal and gateway components of PAN-OS software.
Successful exploitation of the flaw allows unauthenticated remote attackers to sidestep authentication and establish VPN sessions without valid credentials when authentication override cookies are enabled with specific certificate configurations.
"Post-exploitation tradecraft varied across intrusions, from rapid encryption-only operations to full double-extortion, possibly suggesting multiple affiliates operating under the Qilin ransomware-as-a-service (RaaS) umbrella," the cybersecurity company said.
