CVE-2014-9679 in CUPS
Summary
by MITRE
Integer underflow in the cupsRasterReadPixels function in filter/raster.c in CUPS before 2.0.2 allows remote attackers to have unspecified impact via a malformed compressed raster file, which triggers a buffer overflow.
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Analysis
by VulDB Data Team • 03/10/2022
The vulnerability identified as CVE-2014-9679 represents a critical integer underflow condition within the Common Unix Printing System CUPS software version 1.7.5 and earlier. This flaw exists specifically within the cupsRasterReadPixels function located in the filter/raster.c source file, where improper input validation leads to a dangerous arithmetic operation that can result in severe security consequences. The vulnerability manifests when processing malformed compressed raster files, which are commonly used in printing workflows and document processing systems.
The technical implementation of this vulnerability stems from an insufficient bounds check during the parsing of raster data structures. When the cupsRasterReadPixels function processes compressed raster data, it performs arithmetic operations on integer values that control buffer allocation and memory access boundaries. An attacker can manipulate the compressed raster file to cause these integers to underflow, resulting in negative values that subsequently trigger buffer overflow conditions. This occurs because the system allocates memory based on the corrupted integer values, leading to memory regions being accessed beyond their intended boundaries. The underlying issue aligns with CWE-191, which specifically addresses integer underflow conditions, and represents a classic example of improper input validation in memory management operations.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, potentially enabling remote code execution and privilege escalation within affected systems. Attackers can craft malicious compressed raster files that, when processed by vulnerable CUPS versions, cause the application to allocate insufficient memory buffers or access memory regions that should remain protected. This can result in arbitrary code execution with the privileges of the CUPS service, which typically runs with elevated permissions to manage print queues and device communications. The vulnerability affects systems where CUPS serves as a print server or where raster data processing occurs, including enterprise printing environments, web-based printing services, and document management systems that rely on proper raster handling capabilities. According to ATT&CK framework, this vulnerability maps to T1203, which covers Exploitation for Client Execution, and T1068, which addresses Exploitation for Privilege Escalation.
Mitigation strategies for CVE-2014-9679 focus primarily on immediate software updates and comprehensive input validation measures. Organizations should prioritize upgrading to CUPS version 2.0.2 or later, where the integer underflow has been corrected through proper bounds checking and input validation. Additionally, system administrators should implement strict file validation policies that reject compressed raster files from untrusted sources and establish monitoring for unusual print job processing patterns that might indicate exploitation attempts. Network segmentation and access controls should be enforced to limit exposure of vulnerable CUPS instances to untrusted networks. The fix implemented in CUPS 2.0.2 addresses the root cause by ensuring proper integer overflow detection and implementing robust bounds checking mechanisms that prevent the manipulation of memory allocation parameters through malformed input data. Security teams should also consider deploying intrusion detection systems that can identify patterns associated with compressed raster file processing and potential exploitation attempts targeting this specific vulnerability class.