CVE-2018-19636 in Supportutils
Summary
by MITRE
Supportutils, before version 3.1-5.7.1, when run with command line argument -A searched the file system for a ndspath binary. If an attacker provides one at an arbitrary location it is executed with root privileges
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Analysis
by VulDB Data Team • 07/26/2023
The vulnerability identified as CVE-2018-19636 resides within the supportutils package, a tool commonly used for collecting system information and diagnostics in enterprise environments. This flaw represents a classic path traversal and privilege escalation vulnerability that can be exploited by malicious actors to gain elevated system access. The issue manifests when the supportutils utility is executed with the -A command line argument, which triggers a specific code path designed to search for an ndspath binary within the file system. The vulnerability stems from insufficient input validation and improper privilege handling during the binary search process, creating an environment where an attacker can manipulate the system's binary resolution mechanism.
The technical exploitation of this vulnerability occurs through a carefully crafted file system manipulation attack. When supportutils executes with the -A flag, it performs a recursive search for the ndspath binary using a hardcoded search pattern that does not properly validate or sanitize the paths discovered during the search. An attacker who has write access to a directory that gets searched by supportutils can place a malicious binary named ndspath at an arbitrary location, and when the utility executes, it will run the attacker-controlled binary with root privileges due to the elevated execution context. This type of vulnerability falls under CWE-78, which describes improper neutralization of special elements used in OS commands, and specifically relates to CWE-426, which addresses untrusted search path vulnerabilities.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can lead to complete system compromise and persistent backdoor access. Attackers can leverage this vulnerability to execute arbitrary code with root privileges, potentially installing additional malware, modifying system files, or establishing persistent access mechanisms. The vulnerability is particularly dangerous in enterprise environments where supportutils may be executed by system administrators or automated processes, as it can be exploited without requiring direct user interaction or elevated privileges to place the malicious binary initially. This makes the attack surface significantly larger and more difficult to defend against compared to traditional privilege escalation vectors that require pre-existing access to the system.
The attack vector for this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the privilege escalation category, specifically targeting the execution of malicious code with elevated privileges. The vulnerability represents a critical weakness in the principle of least privilege, as it allows code execution with root privileges through a seemingly benign diagnostic tool. Organizations should immediately update their supportutils packages to version 3.1-5.7.1 or later, which contains the necessary patch to resolve the improper path handling. Additional mitigations include restricting write access to directories that may be searched by supportutils, implementing strict file system permissions, and monitoring for unusual execution patterns of system diagnostic tools. Network segmentation and access controls can also help reduce the risk by limiting which users or systems can execute supportutils with the -A flag, thereby reducing the attack surface for this particular vulnerability.