F5 BIG-IP APM Malware Injects a PHP Web Shell Into Memory, Evading Disk Scans

Malware linked to break-ins at F5 BIG-IP Access Policy Manager appliances hides a PHP web shell in memory instead of in a file on disk, Sophos said in an analysis published on September 7. When Apache loads any of the three appliances' own PHP scripts, the malware adds the web shell to the copy...

CISA Adds CVE-2025-53521 to KEV After Active F5 BIG-IP APM Exploitation

The U.S. Cybersecurity and Infrastructure Security Agency CISA on Friday added a critical security flaw impacting F5 BIG-IP Access Policy Manager APM to its Known Exploited Vulnerabilities KEV catalog, citing evidence of active exploitation. The vulnerability in question is CVE-2025-53521 CVSS v4...

CVE-2025-53521 BigIP APM Vulnerability

When a BIG-IP APM access policy is configured on a virtual server, specific malicious traffic can lead to Remote Code Execution RCE. Note: Software versions which have reached End of Technical Support EoTS are not evaluated...

CVE-2025-53521

CVE-2025-53521 affects BIG-IP APM. A stack-based overflow in the APM component can allow unauthenticated remote code execution when an APM access policy is configured on a virtual server. Exploitation has been observed in the wild (per advisories and media). Remediation involves upgrading to fixe...