CVE-2017-13136 in libbpg
Summary
by MITRE
The image_alloc function in bpgenc.c in libbpg 0.9.7 has an integer overflow, with a resultant invalid malloc and NULL pointer dereference.
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Analysis
by VulDB Data Team • 12/07/2019
The vulnerability identified as CVE-2017-13136 resides within the libbpg library version 0.9.7, specifically within the image_alloc function located in the bpgenc.c source file. This issue represents a critical security flaw that stems from improper handling of integer values during memory allocation operations, creating a pathway for potential exploitation. The vulnerability manifests as an integer overflow condition that directly impacts the malloc function's ability to allocate appropriate memory resources, ultimately leading to a NULL pointer dereference scenario that can compromise system stability and potentially enable arbitrary code execution.
The technical root cause of this vulnerability aligns with CWE-190, which describes integer overflow conditions that can result in memory allocation failures and subsequent memory corruption. The image_alloc function processes image dimensions and calculates memory requirements for buffer allocation without adequate validation of input parameters, allowing maliciously crafted image data to trigger arithmetic overflow conditions. When integer overflow occurs during the calculation of memory requirements, the resulting value becomes insufficient to properly allocate memory, causing malloc to either return NULL or allocate an incorrect amount of memory. This faulty memory allocation subsequently leads to a NULL pointer dereference when the application attempts to access the improperly allocated memory region, creating a crash condition or potential exploitation vector.
The operational impact of CVE-2017-13136 extends beyond simple system instability, as it represents a potential entry point for attackers seeking to compromise systems processing bpg image files. The vulnerability can be exploited through crafted image files that trigger the integer overflow condition during the encoding process, making it particularly dangerous in environments where users can upload or process untrusted image content. This flaw affects applications and systems that rely on libbpg for image processing, including web applications, content management systems, and multimedia processing platforms. The vulnerability's classification under the ATT&CK framework would fall under the T1203 - Exploitation for Client Execution tactic, as it enables remote code execution through manipulation of image file processing workflows. Systems utilizing libbpg for image transcoding or encoding operations become vulnerable to denial of service attacks or more severe exploitation scenarios when processing maliciously crafted image files.
Mitigation strategies for CVE-2017-13136 should prioritize immediate remediation through library updates to versions that address the integer overflow vulnerability. System administrators must ensure all affected applications are updated to libbpg versions that contain proper input validation and integer overflow protection mechanisms. The implementation of proper bounds checking and input validation for image dimensions before memory allocation operations should be enforced within affected applications. Additionally, deploying runtime protections such as address space layout randomization and stack canaries can provide defense-in-depth measures against potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify systems utilizing vulnerable versions of libbpg, while network segmentation and access controls can limit the potential impact of successful exploitation attempts. Organizations should also implement proper image validation procedures that reject or sanitize image files before processing to prevent malicious input from reaching the vulnerable library functions.