CVE-2016-9638 in Patrol
Summary
by MITRE
In BMC Patrol before 9.13.10.02, the binary "listguests64" is configured with the setuid bit. However, when executing it, it will look for a binary named "virsh" using the PATH environment variable. The "listguests64" program will then run "virsh" using root privileges. This allows local users to elevate their privileges to root.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/04/2022
The vulnerability described in CVE-2016-9638 represents a critical privilege escalation flaw within BMC Patrol software versions prior to 9.13.10.02. This issue stems from improper privilege management and insecure path resolution mechanisms that create a dangerous execution environment for system binaries. The vulnerability specifically targets the "listguests64" binary which is configured with the setuid bit, granting it elevated privileges during execution. When this binary executes, it searches for the "virsh" command using the standard PATH environment variable without proper validation or sanitization of the search path. This design flaw creates an exploitable condition where a malicious user can manipulate the environment to execute arbitrary code with root privileges.
The technical implementation of this vulnerability aligns with CWE-426 Untrusted Search Path, which describes how applications that search for executables in untrusted locations can be exploited to execute malicious code. The flaw demonstrates a classic insecure programming pattern where the application assumes that PATH-based lookups will resolve to legitimate system binaries while failing to account for potential path manipulation attacks. The setuid bit on "listguests64" creates a privileged execution context that should only be accessible to authorized system components, but the insecure execution of "virsh" through PATH resolution undermines this security boundary. This vulnerability operates under the ATT&CK framework category of Privilege Escalation through the use of setuid binaries and environment variable manipulation to achieve unauthorized root access.
The operational impact of this vulnerability is severe as it allows local attackers to achieve complete system compromise without requiring any external network access or authentication. Attackers can exploit this by placing a malicious "virsh" binary in a directory that appears earlier in the PATH variable, causing the privileged "listguests64" program to execute their malicious code with root privileges. This creates a persistent backdoor condition that can be used to maintain administrative access to the compromised system. The vulnerability affects systems running BMC Patrol versions below 9.13.10.02 and represents a fundamental failure in privilege management and binary execution security. Organizations using affected versions face significant risk of unauthorized system access and potential data breaches.
Mitigation strategies for CVE-2016-9638 should focus on immediate patching of BMC Patrol to version 9.13.10.02 or later where the vulnerability has been addressed. System administrators should also implement additional security controls including verifying the integrity of setuid binaries through checksum validation, implementing strict PATH environment variable restrictions, and monitoring for unauthorized binary modifications. The principle of least privilege should be enforced by reviewing all setuid binaries and ensuring they are necessary for system operation. Additionally, organizations should implement process monitoring to detect suspicious execution patterns and consider using tools like SELinux or AppArmor to restrict the execution environment of privileged binaries. Regular security audits of system binaries and environment configurations should be conducted to identify and remediate similar vulnerabilities across the infrastructure.