CVE-2008-5110 in syslog-ng
Summary
by MITRE
syslog-ng does not call chdir when it calls chroot, which might allow attackers to escape the intended jail. NOTE: this is only a vulnerability when a separate vulnerability is present.
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Analysis
by VulDB Data Team • 08/21/2019
The vulnerability identified as CVE-2008-5110 affects the syslog-ng system logging daemon and represents a privilege escalation weakness that stems from improper directory handling during process initialization. This flaw specifically occurs when syslog-ng executes chroot operations without subsequently calling chdir to change the working directory to the new root filesystem. The technical nature of this vulnerability places it within the scope of CWE-252, which deals with insufficient privilege management and improper handling of system call sequences. When an attacker can manipulate the environment or exploit a separate vulnerability that allows them to access the system before or during the chroot process, they may be able to escape the intended chroot jail and gain elevated privileges.
The operational impact of this vulnerability becomes significant when considering the typical deployment model of syslog-ng, which often runs with elevated privileges to access system logs and manage logging operations across various system components. The vulnerability creates a window of opportunity where an attacker could leverage the improper chroot sequence to navigate to directories outside the intended jail environment. This flaw aligns with ATT&CK technique T1068 which covers local privilege escalation through improper system call sequences and path manipulation. The vulnerability is particularly dangerous because it does not represent a standalone exploit but rather a weakness that compounds with other existing vulnerabilities, making it more difficult to detect and remediate.
The technical execution of this vulnerability requires a specific sequence of events where an attacker must first exploit another vulnerability to gain initial access or control over the system. Once this initial compromise is achieved, the attacker can then leverage the improper chdir behavior following chroot to escape the restricted environment. This chaining of vulnerabilities demonstrates how seemingly minor implementation flaws in system components can create significant security risks when combined with other attack vectors. The vulnerability exists primarily in the process initialization sequence where the application fails to properly establish the working directory after changing the root filesystem, leaving potential paths accessible outside the intended security boundaries. This weakness is particularly concerning in environments where syslog-ng is used as a critical logging service that requires elevated privileges for proper operation.
Mitigation strategies for CVE-2008-5110 should focus on ensuring that all system components properly implement the complete chroot sequence including proper directory changes after root filesystem modification. System administrators should ensure that syslog-ng is updated to versions that properly handle the chroot and chdir operations in the correct sequence. The implementation should follow security best practices where chroot operations are always followed by chdir to the new root directory to prevent potential escape paths. Additionally, comprehensive system hardening measures including proper privilege separation, regular security updates, and monitoring for unauthorized access attempts should be implemented. Organizations should also consider implementing additional security controls such as mandatory access controls, file integrity monitoring, and regular security assessments to detect and prevent exploitation of this type of vulnerability. The vulnerability serves as a reminder of the importance of proper system call sequencing and the potential for seemingly minor implementation flaws to create significant security risks when combined with other attack vectors.