CVE-2025-48500: F5 BIG-IP APM Privilege Escalation Flaw

CVE-2025-48500 Overview

CVE-2025-48500 is a missing file integrity check vulnerability [CWE-353] affecting the F5 VPN browser client installer for macOS. The flaw allows a local, authenticated attacker with access to the local file system to replace the legitimate installer with a malicious package. When a user subsequently executes the installer, the attacker's code runs with the privileges granted during installation. F5 notes that software versions which have reached End of Technical Support (EoTS) are not evaluated.

Critical Impact
An attacker who can write to the installer path can substitute a trojanized .pkg file, leading to full compromise of confidentiality, integrity, and availability on the affected macOS host.

Affected Products

F5 BIG-IP Access Policy Manager (APM)
F5 BIG-IP Access Policy Manager Client 7.2.5
Apple macOS (as the installer host platform)

Discovery Timeline

2025-08-13 - CVE-2025-48500 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-48500

Vulnerability Analysis

The F5 VPN browser client installer for macOS does not validate the integrity of the installer package before execution. The installer lacks a cryptographic signature verification or checksum comparison step that would detect tampering. This maps to CWE-353, Missing Support for Integrity Check.

An attacker who has already authenticated to the macOS system and holds write access to the directory containing the installer can swap the legitimate .pkg with a malicious payload. When a privileged user launches the installer, macOS executes the substituted package. The attack requires user interaction, meaning the victim must run the tampered installer for exploitation to succeed.

Exploitation results in local code execution in the context of the installing user. Because macOS installers commonly request administrator credentials during package installation, the malicious payload can escalate to root-level operations through legitimate installer scripting mechanisms such as preinstall and postinstall scripts.

Root Cause

The root cause is the absence of an integrity verification step in the client installer distribution and execution workflow. Without validating the installer's signature or hash against a trusted reference, the client cannot distinguish a legitimate F5 package from an attacker-controlled substitute.

Attack Vector

The attack vector is local and requires prior authenticated access to the macOS host, along with user interaction to execute the substituted installer. A typical scenario involves a low-privileged user, malware, or a lateral-movement foothold placing a malicious package in the location where an administrator will later run the F5 VPN installer.

No verified public proof-of-concept code is available. The vulnerability mechanism is straightforward file substitution against an installer that does not verify its own integrity. Refer to the F5 Support Article K000151782 for vendor-specific guidance.

Detection Methods for CVE-2025-48500

Indicators of Compromise

Unexpected modifications to F5 VPN installer .pkg files in user download directories or shared staging locations.
Installer packages whose Developer ID signature does not match F5 Networks, or that fail pkgutil --check-signature verification.
installer process activity spawning unusual child processes or writing to non-standard paths during F5 client installation.

Detection Strategies

Monitor file writes to directories that store the F5 VPN installer and alert on modifications by processes other than the browser or authorized management tools.
Baseline the SHA-256 hash of the approved F5 installer distributed by IT and compare on-disk copies against that reference before execution.
Correlate installer command invocations with the signing authority of the target package using macOS Endpoint Security telemetry.

Monitoring Recommendations

Enable macOS Unified Log collection for com.apple.install subsystem events and forward them to a central analytics platform.
Track process ancestry for preinstall and postinstall script execution originating from F5-branded packages.
Audit privileged authorization prompts (authd) triggered by installer processes for anomalous frequency or timing.

How to Mitigate CVE-2025-48500

Immediate Actions Required

Restrict local file system write access to directories that stage the F5 VPN client installer to administrators only.
Distribute the installer through a managed software deployment channel such as Jamf, Munki, or Intune rather than ad hoc downloads.
Manually verify the installer signature with pkgutil --check-signature before execution on any macOS host.
Review F5 BIG-IP APM Client deployments and identify any hosts running version 7.2.5 for remediation.

Patch Information

F5 has published remediation guidance in F5 Support Article K000151782. Administrators should consult the advisory for fixed client versions and apply the vendor-supplied update. Versions that have reached End of Technical Support are not evaluated and should be replaced with a supported release.

Workarounds

Store the installer in a location writable only by root, such as /Library/Management/F5/, and remove world- or group-writable permissions.
Require installation exclusively via a mobile device management (MDM) platform that pushes the package from a trusted repository.
Enforce Gatekeeper and notarization policies so unsigned or tampered packages are blocked at execution time.

bash

# Verify installer signature and hash before execution
pkgutil --check-signature /path/to/F5VPNClient.pkg
shasum -a 256 /path/to/F5VPNClient.pkg

# Restrict installer directory permissions to root
sudo chown root:wheel /Library/Management/F5/
sudo chmod 755 /Library/Management/F5/
sudo chmod 644 /Library/Management/F5/F5VPNClient.pkg