CVE-2008-4947 in dhis-server
Summary
by MITRE
dhis-dummy-log-engine in dhis-server 5.3 allows local users to overwrite arbitrary files via a symlink attack on the /tmp/dhis-dummy-log-engine.log temporary file.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/13/2018
The vulnerability identified as CVE-2008-4947 represents a critical path traversal and symbolic link attack flaw within the dhis-dummy-log-engine component of the dhis-server 5.3 software suite. This issue specifically affects local users who can exploit a race condition in the temporary file creation process to manipulate system files through carefully crafted symbolic links. The vulnerability resides in the improper handling of temporary file paths during log file operations, creating an attack surface that can be leveraged by malicious users with local system access to overwrite arbitrary files with controlled content.
The technical exploitation mechanism relies on a classic race condition vulnerability where the dhis-dummy-log-engine component creates temporary log files without proper atomic operations or secure temporary file handling practices. When the application attempts to create the log file at /tmp/dhis-dummy-log-engine.log, an attacker can establish a symbolic link with the same name pointing to a target file of their choice. Due to the lack of proper validation and secure file creation procedures, the application writes log data to the symbolic link target rather than the intended temporary file, enabling arbitrary file overwrite operations. This flaw directly maps to CWE-377: Insecure Temporary File and CWE-367: Time-of-Check to Time-of-Use vulnerability patterns, which are commonly exploited in privilege escalation and persistence attacks.
The operational impact of this vulnerability extends beyond simple file overwrites to encompass potential privilege escalation and system compromise scenarios. Local attackers can leverage this vulnerability to overwrite critical system files, configuration files, or even executable binaries with malicious content, potentially leading to persistent backdoors or complete system compromise. The attack requires local system access but does not necessitate network connectivity or elevated privileges, making it particularly dangerous in environments where local user accounts have access to the dhis-server processes. This vulnerability can be exploited to maintain persistence, escalate privileges, or cause denial of service conditions by overwriting essential system components.
Mitigation strategies for CVE-2008-4947 should focus on implementing secure temporary file handling practices and eliminating race conditions in the application code. System administrators should ensure that the dhis-server components are updated to versions that properly implement atomic temporary file creation using secure methods such as creating files with restrictive permissions and using secure temporary file APIs. The recommended approach includes implementing proper file path validation, using secure temporary file creation functions that prevent symbolic link attacks, and ensuring that temporary files are created with appropriate permissions that prevent unauthorized access or modification. Additionally, privilege separation and least privilege principles should be enforced to limit the impact of potential exploitation, and regular security audits should be conducted to identify similar vulnerabilities in other system components. This vulnerability aligns with ATT&CK technique T1059.007 for execution through scripts and T1548.001 for privilege escalation, emphasizing the need for comprehensive security measures beyond simple patching.