CVE-2000-0803 in Groff
Summary
by MITRE
GNU Groff uses the current working directory to find a device description file, which allows a local user to gain additional privileges by including a malicious postpro directive in the description file, which is executed when another user runs groff.
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Analysis
by VulDB Data Team • 04/06/2019
The vulnerability identified as CVE-2000-0803 resides within the GNU Groff document formatting system, specifically targeting how the software handles device description files during processing. This flaw represents a classic privilege escalation vulnerability that exploits the software's reliance on the current working directory for file resolution. When groff processes documents, it searches for device description files in the current working directory before examining system paths, creating an exploitable condition where a malicious user can manipulate the file resolution process.
The technical mechanism of this vulnerability operates through the postpro directive functionality within groff's device description files. When a user includes a malicious postpro directive in a crafted device description file, the system executes this code with the privileges of the user running groff. This creates a scenario where an attacker can place a malicious device description file in a directory where another user might run groff, effectively allowing the attacker to execute arbitrary code with the privileges of that user. The vulnerability is particularly dangerous because it leverages the trust relationship between the software and the current working directory.
From an operational perspective, this vulnerability poses significant risks in multi-user environments where users share common directories or where users might inadvertently process documents from untrusted sources. The attack vector requires local access to the system and knowledge of when and how groff will be invoked by other users, but once exploited, it can provide persistent access to compromised systems. The vulnerability affects systems where groff is used for document processing and where users might encounter documents from untrusted sources, particularly in environments with shared file systems or collaborative workspaces.
The security implications extend beyond simple privilege escalation to encompass potential system compromise and data exfiltration capabilities. Attackers can leverage this vulnerability to install backdoors, modify system files, or establish persistent access to compromised systems. This vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and represents a path traversal attack that bypasses normal security boundaries. The attack pattern corresponds to techniques described in the MITRE ATT&CK framework under privilege escalation and execution categories, specifically targeting the execution of malicious code through document processing utilities.
Mitigation strategies for this vulnerability involve multiple layers of defense including updating to patched versions of GNU Groff, implementing proper file permissions and directory access controls, and employing sandboxing techniques for document processing. System administrators should also consider implementing monitoring for suspicious groff usage patterns and establishing secure document handling procedures. The most effective long-term solution involves ensuring that all systems are running patched versions of GNU Groff and that users are educated about the risks of processing documents from untrusted sources, particularly in collaborative environments where shared directories might contain maliciously crafted device description files.