CVE-2018-5546 in BIG-IP APM Client
Summary
by MITRE
The svpn and policyserver components of the F5 BIG-IP APM client prior to version 7.1.7.1 for Linux and macOS runs as a privileged process and can allow an unprivileged user to get ownership of files owned by root on the local client host. A malicious local unprivileged user may gain knowledge of sensitive information, manipulate certain data, or assume super-user privileges on the local client host.
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Analysis
by VulDB Data Team • 05/02/2023
The CVE-2018-5546 vulnerability affects the F5 BIG-IP APM client components including svpn and policyserver on Linux and macOS systems. This represents a critical privilege escalation flaw that allows unprivileged local users to gain root-level access to the affected systems. The vulnerability stems from the design of these components which run with elevated privileges despite being part of a client-side application. When these processes execute with root permissions, they create an attack surface that malicious users can exploit to compromise the entire system.
The technical flaw manifests through improper privilege management within the F5 BIG-IP APM client implementation. The svpn and policyserver processes are designed to operate with root privileges, but they fail to properly validate or restrict access controls when handling file operations. This design flaw creates a path for local users to manipulate file ownership and gain elevated privileges. The vulnerability is particularly dangerous because it allows attackers to access files that should normally be restricted to root users, potentially exposing sensitive system information, configuration files, or cryptographic keys. The issue is classified as a privilege escalation vulnerability and maps to CWE-276 which addresses improper file permissions and access control mechanisms.
From an operational impact perspective, this vulnerability represents a severe threat to organizations relying on F5 BIG-IP APM clients for remote access management. An attacker who gains access to a local user account can leverage this flaw to escalate privileges and achieve full system compromise. The attack vector is particularly concerning because it requires only local access, making it difficult to detect through network monitoring tools. Once escalated to root privileges, attackers can manipulate system files, install persistent backdoors, exfiltrate sensitive data, or disable security controls. The vulnerability essentially provides a backdoor mechanism that bypasses traditional network-based security measures, making it a significant concern for enterprise environments where endpoint security is paramount.
Organizations should immediately apply the vendor-provided patches for F5 BIG-IP APM client versions prior to 7.1.7.1 to remediate this vulnerability. System administrators should also implement additional security controls including mandatory access controls, file integrity monitoring, and regular privilege audits. The mitigation strategy should include disabling unnecessary client components and ensuring proper user access controls are in place. This vulnerability aligns with ATT&CK technique T1068 which covers privilege escalation through local exploitation, and T1548 which addresses abuse of system privileges. Organizations should also consider implementing endpoint detection and response solutions to monitor for suspicious file access patterns and privilege escalation attempts. Regular security assessments of client-side applications are essential to identify similar privilege management flaws that could be exploited by malicious actors.