CVE-2011-0343 in syslog-ng
Summary
by MITRE
Balabit syslog-ng 2.0, 3.0, 3.1, 3.2 OSE and PE, when running on FreeBSD or HP-UX, does not properly perform cast operations, which causes syslog-ng to use a default value of -1 to create log files with insecure permissions (07777), which allows local users to read and write to these log files.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 04/24/2018
The vulnerability identified as CVE-2011-0343 affects syslog-ng versions 2.0, 3.0, 3.1, and 3.2 across both Open Source Edition and Professional Edition when deployed on FreeBSD or HP-UX operating systems. This issue stems from improper cast operations within the syslog-ng logging daemon implementation, creating a critical security flaw that undermines the integrity of log file permissions. The vulnerability manifests when syslog-ng attempts to create log files with insecure permission settings, specifically defaulting to 07777 permissions which grant excessive access rights to all system users. This improper handling of file permissions represents a significant deviation from standard security practices and creates a persistent threat vector for local privilege escalation attacks.
The technical root cause of this vulnerability lies in the type casting mechanisms within syslog-ng's file creation routines. When processing log file operations on FreeBSD and HP-UX systems, the application fails to properly validate and cast data types during permission setting operations. This casting error results in the system defaulting to a value of -1, which subsequently translates into an incorrect permission mask of 07777. According to CWE-704, this represents a weakness in data type conversion that leads to unexpected behavior and security implications. The improper casting operation creates a scenario where the application cannot correctly determine the intended file permissions, leading to the creation of log files with overly permissive access controls.
The operational impact of this vulnerability extends beyond simple permission misconfiguration, creating a persistent security risk that can be exploited by local attackers to gain unauthorized access to sensitive system information. When log files are created with 07777 permissions, any user on the system can read, write, and modify these files, potentially allowing malicious actors to inject false log entries, corrupt system logs, or even execute arbitrary code through log file manipulation. This vulnerability directly aligns with ATT&CK technique T1562.006 for "Impairing Security Tools" and represents a classic case of insecure file handling that can be leveraged for privilege escalation. The impact is particularly severe on systems where syslog-ng is used to manage critical system logging, as compromised log files can undermine forensic analysis and security monitoring capabilities.
The security implications of this vulnerability are compounded by the fact that it affects multiple versions of syslog-ng across different editions, indicating a systemic issue within the codebase rather than a isolated incident. System administrators and security professionals should recognize that this vulnerability can be exploited to undermine the fundamental security posture of systems relying on syslog-ng for log management. The default value of -1 being interpreted as 07777 permissions creates a consistent threat across all affected platforms and versions, making this vulnerability particularly dangerous for organizations with multiple syslog-ng installations. Organizations should immediately implement patch management procedures to address this vulnerability, as the insecure permissions can be exploited to create persistent backdoors or to hide malicious activities within system logs. This vulnerability serves as a reminder of the critical importance of proper type handling and permission validation in security-critical system components, particularly in logging daemons that handle sensitive operational data.