CVE-2000-0791 in Secure Linux
Summary
by MITRE
Trustix installs the httpsd program for Apache-SSL with world-writeable permissions, which allows local users to replace it with a Trojan horse.
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Analysis
by VulDB Data Team • 04/06/2019
The vulnerability described in CVE-2000-0791 represents a critical privilege escalation issue within the Trustix Linux distribution's implementation of Apache-SSL web server configuration. This flaw stems from improper permission settings during the installation process of the httpsd program, which serves as the daemon responsible for managing secure HTTP connections through SSL encryption. The security compromise occurs when the installation script fails to properly secure the httpsd binary by setting restrictive permissions, instead leaving it with world-writable access rights that permit any local user to modify or replace the executable file.
The technical nature of this vulnerability aligns with CWE-732, which addresses improper permission assignment where a system component is created with insecure permissions that allow unauthorized modification. The httpsd program, being a critical system component that handles secure web traffic and authentication, becomes a prime target for malicious actors who can substitute the legitimate binary with a malicious Trojan horse version. This Trojan horse implementation could potentially log user credentials, redirect traffic to malicious servers, or provide backdoor access to the compromised system while maintaining the appearance of normal operation.
From an operational impact perspective, this vulnerability enables local users to achieve privilege escalation from their current access level to that of the root user or the user account under which the httpsd daemon runs. The attack vector is particularly concerning because it requires no network connectivity or external exploitation techniques - simply local access to the system is sufficient to compromise the entire web server infrastructure. The compromised system could then serve as a pivot point for further attacks within a network, potentially allowing attackers to access sensitive data, modify web content, or use the compromised server as a launching point for attacks against other systems.
The attack methodology follows patterns consistent with ATT&CK technique T1068, which involves local privilege escalation through exploitation of weak permissions and system misconfigurations. An attacker would first gain access to the local system, then locate the httpsd binary, and finally replace it with a malicious version that maintains the same interface and functionality while executing unauthorized code. The remediation strategy involves immediately correcting the file permissions on the httpsd binary to ensure it is not world-writable, typically through chmod operations that restrict write access to the root user or specific administrative groups. Additionally, system administrators should implement regular permission audits and consider implementing file integrity monitoring solutions to detect unauthorized modifications to critical system binaries, as outlined in security best practices for maintaining system integrity and preventing privilege escalation attacks.