CVE-2014-4336 in cups-filters
Summary
by MITRE
The generate_local_queue function in utils/cups-browsed.c in cups-browsed in cups-filters before 1.0.53 allows remote IPP printers to execute arbitrary commands via shell metacharacters in the host name. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-2707.
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Analysis
by VulDB Data Team • 03/10/2019
The vulnerability identified as CVE-2014-4336 represents a critical command injection flaw within the cups-browsed component of the cups-filters package, affecting versions prior to 1.0.53. This issue specifically targets the generate_local_queue function located in utils/cups-browsed.c, which processes IPP printer information and constructs local queue names. The vulnerability arises from inadequate input validation when handling host names provided by remote IPP printers, creating a pathway for malicious command execution through shell metacharacters. The flaw is particularly concerning as it builds upon a previous vulnerability CVE-2014-2707, indicating that the initial remediation was incomplete or insufficient, leaving the system exposed to similar attack vectors. This represents a classic case of improper input sanitization where user-controllable data flows directly into shell execution contexts without adequate filtering or escaping mechanisms.
The technical exploitation of this vulnerability occurs when a remote IPP printer advertises itself with a specially crafted host name containing shell metacharacters such as semicolons, ampersands, or backticks. When cups-browsed processes this information through the generate_local_queue function, it fails to properly escape or sanitize these characters before incorporating them into system commands. This allows attackers to inject arbitrary shell commands that execute with the privileges of the cups-browsed process, typically running with elevated permissions to manage printer queues. The vulnerability falls under CWE-78, which specifically addresses improper neutralization of special elements used in shell commands, and aligns with ATT&CK technique T1059.001 for command and script interpreter execution. The attack surface is particularly broad as it can be exploited through any IPP printer that supports the cups-browsed discovery mechanism, making it a significant threat in networked printing environments where multiple devices may be automatically discovered and configured.
The operational impact of CVE-2014-4336 extends beyond simple command execution, potentially allowing attackers to gain unauthorized access to network resources, escalate privileges, or compromise entire print server infrastructures. In environments where cups-browsed operates with administrative privileges, successful exploitation could enable attackers to modify printer configurations, redirect print jobs, or even establish persistent access points through compromised printer queue management. The vulnerability affects systems that automatically discover and configure IPP printers, particularly those running Linux distributions with cups-filters packages, making it relevant to enterprise printing environments, educational institutions, and organizations relying on automatic printer discovery mechanisms. Organizations with unpatched systems remain vulnerable to remote exploitation, as the attack requires no authentication and can be initiated by any device capable of advertising an IPP printer with malicious host name data.
Mitigation strategies for CVE-2014-4336 primarily focus on immediate patching of the cups-filters package to version 1.0.53 or later, which contains the complete fix for both CVE-2014-2707 and CVE-2014-4336. Network administrators should also implement restrictive firewall policies that limit IPP printer discovery traffic to trusted networks, reducing the attack surface by preventing unauthorized printers from advertising themselves to the cups-browsed service. Additional protective measures include configuring cups-browsed with restricted execution contexts, implementing input validation at the network level, and monitoring for unusual printer queue creation or modification activities. Organizations should also consider disabling automatic printer discovery features when not required, and implementing network segmentation to isolate printing services from critical infrastructure. The remediation process should include thorough testing of the patched environment to ensure that legitimate printer configurations continue to function properly while eliminating the command injection vulnerability that could be exploited by remote attackers.