CVE-2007-0476 in OpenLDAP
Summary
by MITRE
The gencert.sh script, when installing OpenLDAP before 2.1.30-r10, 2.2.x before 2.2.28-r7, and 2.3.x before 2.3.30-r2 as an ebuild in Gentoo Linux, does not create temporary directories in /tmp securely during emerge, which allows local users to overwrite arbitrary files via a symlink attack.
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Analysis
by VulDB Data Team • 07/14/2019
The vulnerability described in CVE-2007-0476 represents a critical insecure temporary file creation flaw within the OpenLDAP package installation process on Gentoo Linux systems. This issue specifically affects the gencert.sh script that is executed during the emerge process for OpenLDAP packages across multiple version branches including 2.1.x, 2.2.x, and 2.3.x. The flaw stems from the script's failure to properly secure temporary directory creation in the /tmp filesystem, creating a path traversal vulnerability that can be exploited by local attackers.
The technical implementation of this vulnerability involves the gencert.sh script creating temporary directories without proper security measures such as using secure temporary directory creation functions or implementing proper file permissions. When the script executes during package installation, it creates temporary files and directories in /tmp without ensuring their security properties, which enables a malicious local user to perform a symlink attack. This attack occurs when an attacker creates symbolic links in the /tmp directory that point to sensitive files or directories, allowing the vulnerable script to inadvertently overwrite or modify these targets during its execution.
The operational impact of this vulnerability is significant as it allows local privilege escalation and arbitrary file modification capabilities. An attacker with local access to a system can leverage this vulnerability to overwrite critical system files, configuration files, or even files owned by other users or system processes. This creates a potential vector for persistent access, data corruption, or privilege escalation within the affected system environment. The vulnerability affects the entire package management ecosystem of Gentoo Linux, as it operates during the emerge process which is fundamental to system package installation and updates.
From a cybersecurity perspective, this vulnerability aligns with CWE-355 - Security-Related OS Quality Issues and CWE-377 - Insecure Temporary File, both of which address the fundamental security principles of temporary file handling in operating systems. The attack pattern corresponds to the MITRE ATT&CK framework's technique T1059.007 - Command and Scripting Interpreter: PowerShell, though more specifically relates to T1068 - Exploitation for Privilege Escalation and T1548.001 - Abuse Elevation Control Mechanism: Bypass User Account Control. The vulnerability demonstrates a classic insecure file handling pattern that can be exploited through the principle of least privilege violation, where temporary files are created with inadequate security controls.
The recommended mitigations for this vulnerability include immediate patching of affected OpenLDAP versions to the secure releases mentioned in the CVE description, specifically versions 2.1.30-r10, 2.2.28-r7, and 2.3.30-r2. System administrators should also implement proper temporary file handling practices such as using mkdtemp() or similar secure temporary directory creation functions, implementing proper file permissions and ownership checks, and ensuring that temporary directories are created with restrictive permissions. Additionally, monitoring for unauthorized symlink creation in the /tmp directory and implementing proper file system hardening measures can help detect and prevent exploitation attempts. Organizations should also consider implementing privilege separation mechanisms and regularly auditing package installation processes to identify similar insecure temporary file handling patterns across their systems.