CVE-2013-6473 in cups-filters
Summary
by MITRE
Multiple heap-based buffer overflows in the urftopdf filter in cups-filters 1.0.25 before 1.0.47 allow remote attackers to execute arbitrary code via a large (1) page or (2) line in a URF file.
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Analysis
by VulDB Data Team • 05/08/2026
The vulnerability identified as CVE-2013-6473 represents a critical heap-based buffer overflow in the urftopdf filter component of cups-filters version 1.0.25 and earlier. This flaw exists within the Universal Raster Format processing pipeline that converts URF files to PDF documents, making it particularly dangerous in print server environments where multiple users submit print jobs. The vulnerability specifically affects the handling of page and line data within URF files, creating conditions where attacker-controlled input can overflow allocated memory buffers on the heap. The flaw stems from insufficient bounds checking when processing raster data structures, allowing malicious input to overwrite adjacent memory locations and potentially corrupt program execution flow. This issue falls under CWE-121 Heap-based Buffer Overflow, which is classified as a severe memory safety vulnerability that can lead to arbitrary code execution. The attack vector requires remote exploitation through crafted URF files submitted to a vulnerable print server, making it particularly concerning for networked printing environments where print queues are accessible over the network. The vulnerability is particularly dangerous because URF files are commonly used in printer communication protocols and can be generated by various applications, increasing the potential attack surface.
The technical implementation of this vulnerability occurs during the conversion process when the urftopdf filter processes URF file structures containing excessive page or line specifications. When a URF file contains malformed data indicating an unusually large number of pages or lines, the filter fails to validate these values against allocated buffer boundaries. This allows attackers to craft malicious URF files that cause the heap allocator to write data beyond the intended buffer limits, potentially overwriting critical program data structures, return addresses, or function pointers. The heap-based nature of the vulnerability means that memory corruption occurs in the heap memory region rather than on the stack, making exploitation more complex but still highly effective. Attackers can leverage this weakness to execute arbitrary code with the privileges of the print server process, which typically runs with elevated permissions to manage printer operations and access system resources. The vulnerability can be exploited in both local and remote scenarios, as print servers often accept print jobs from networked clients without sufficient input validation. This type of vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could lead to command execution on the target system, and T1068 for exploit for privilege escalation, since print server processes often have elevated system privileges.
The operational impact of CVE-2013-6473 extends beyond simple code execution to encompass complete system compromise in vulnerable environments. Print servers running affected versions of cups-filters become potential entry points for attackers seeking to establish persistent access to networked environments, particularly in enterprise settings where print infrastructure serves as a critical component of business operations. The vulnerability can be exploited to gain unauthorized access to sensitive documents processed through the print queue, potentially exposing confidential data in transit. Additionally, the exploitation could lead to denial of service conditions where legitimate print jobs fail due to heap corruption, disrupting business operations. Organizations using this software in cloud printing services or shared print environments face increased risk as attackers can target multiple users through a single vulnerable print server. The vulnerability affects a wide range of systems including servers running Linux distributions, Unix systems, and Windows systems with CUPS print server implementations. The attack requires minimal privileges to execute and can be automated, making it particularly attractive to threat actors seeking to compromise print infrastructure as part of broader network infiltration campaigns. Security professionals should consider this vulnerability when assessing the attack surface of print management systems, as it represents a common vector for initial access in environments where print servers are not adequately secured. The vulnerability demonstrates the importance of input validation in filter and conversion utilities, as these components often process untrusted data from multiple sources without sufficient sanitization measures. Organizations should implement proper access controls, network segmentation, and regular security updates to protect against exploitation attempts targeting this specific vulnerability.
Mitigation strategies for CVE-2013-6473 focus on immediate remediation through software updates and enhanced input validation measures. The primary solution involves upgrading cups-filters to version 1.0.47 or later, which includes patches addressing the heap overflow conditions in the urftopdf filter. System administrators should conduct comprehensive vulnerability assessments to identify all affected print servers and ensure proper patch management protocols are in place. Network segmentation should be implemented to isolate print servers from critical network segments, reducing the potential impact of successful exploitation. Input validation should be strengthened at multiple levels including application-level checks for URF file parameters, protocol-level restrictions on print job sizes, and implementation of sandboxing mechanisms for print processing components. Additional protective measures include implementing strict access controls on print queues, enabling logging and monitoring of print job submissions, and deploying intrusion detection systems to identify suspicious print job patterns. Organizations should also consider disabling unnecessary print protocols and services to minimize attack surface, particularly focusing on the URF processing capabilities that expose this vulnerability. Regular security testing including penetration testing of print infrastructure and automated vulnerability scanning should be conducted to identify similar vulnerabilities in print server configurations. The vulnerability highlights the importance of maintaining up-to-date software libraries and components, as well as implementing defense-in-depth strategies that protect against exploitation of multiple attack vectors within print server environments. Security teams should also establish incident response procedures specifically tailored to print server compromises, given the potential for these systems to serve as initial access points for broader network attacks.