CVE-2016-5759 in Administrator
Summary
by MITRE
The mkdumprd script called "dracut" in the current working directory "." allows local users to trick the administrator into executing code as root.
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Analysis
by VulDB Data Team • 09/26/2024
The vulnerability identified as CVE-2016-5759 resides within the dracut script execution mechanism, specifically targeting the mkdumprd utility that is part of the dracut framework used for creating initramfs images. This flaw represents a classic privilege escalation vector that exploits the trust relationship between system administrators and automated build processes. The vulnerability manifests when the dracut script attempts to execute mkdumprd from the current working directory, creating an environment where malicious code can be injected and executed with elevated privileges. The attack requires local user access and relies on social engineering tactics to deceive administrators into running compromised scripts. The core technical issue stems from the insecure execution pattern that does not properly validate or sanitize the execution path of the mkdumprd utility, allowing attackers to place malicious binaries in the current working directory with the same name as the legitimate utility.
This vulnerability aligns with CWE-426, which addresses the insecure execution of external programs, and demonstrates how command injection flaws can be exploited in automated build and deployment environments. The operational impact is significant as it allows local users to escalate privileges to root level, effectively bypassing all standard user permission controls. The attack scenario typically involves an attacker placing a malicious mkdumprd binary in a directory that appears early in the PATH or in the current working directory where the dracut script executes. When an administrator subsequently runs the dracut script, either manually or through automated processes, the malicious binary gets executed with root privileges, providing the attacker with complete system control. The vulnerability is particularly dangerous in environments where administrators regularly execute build scripts or system maintenance tasks that invoke dracut functionality.
The attack surface is broad and affects systems using the dracut framework for initramfs creation, which is common in many enterprise Linux distributions and server environments. The exploitation requires minimal privileges and can be automated, making it particularly attractive to attackers seeking persistent access. From an ATT&CK perspective, this vulnerability maps to privilege escalation techniques and specifically to T1068, which involves the exploitation of legitimate credentials and system tools. The vulnerability also intersects with T1546, covering the execution of malicious code through legitimate system processes. Organizations running systems with dracut-based initramfs generation are at risk, particularly those with less strict security controls around script execution paths and those where administrators routinely execute system maintenance scripts without proper environment isolation. The risk is amplified in environments where multiple users share system resources or where script execution is not properly audited.
Mitigation strategies must address both the immediate technical flaw and broader system security practices. The most effective immediate fix involves modifying the dracut script to explicitly specify full paths to the mkdumprd utility rather than relying on PATH resolution. This approach prevents the execution of malicious binaries from arbitrary locations. System administrators should also implement proper file system permissions and access controls to limit where malicious code can be placed. Additionally, implementing environment variable sanitization and using tools like SELinux or AppArmor can provide additional layers of protection. Organizations should conduct regular security audits of system scripts and build processes to identify similar insecure execution patterns. The vulnerability also highlights the importance of principle of least privilege and proper script execution environments, where system maintenance tasks should be executed in isolated, secure environments with minimal access to system resources. Regular security training for system administrators about the risks of executing scripts from untrusted locations is also crucial for preventing exploitation.