CVE-2017-6887 in LibRaw
Summary
by MITRE
A boundary error within the "parse_tiff_ifd()" function (internal/dcraw_common.cpp) in LibRaw versions before 0.18.2 can be exploited to cause a memory corruption via e.g. a specially crafted KDC file with model set to "DSLR-A100" and containing multiple sequences of 0x100 and 0x14A TAGs.
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Analysis
by VulDB Data Team • 12/06/2022
The vulnerability identified as CVE-2017-6887 represents a critical boundary error within the LibRaw library's image processing functionality. This flaw exists in the parse_tiff_ifd() function located in the internal/dcraw_common.cpp file, affecting all versions prior to 0.18.2. The issue manifests when processing specially crafted KDC files that utilize the "DSLR-A100" model designation, creating a scenario where multiple sequences of 0x100 and 0x14A TAGs are present in the file structure. The root cause of this vulnerability aligns with CWE-129, which addresses improper validation of array indices, and specifically relates to inadequate bounds checking in memory allocation operations.
The technical exploitation of this vulnerability occurs through a carefully constructed TIFF image file format that triggers a buffer overflow condition during the parsing process. When the parse_tiff_ifd() function processes the malicious KDC file, it fails to properly validate the boundaries of memory allocations, allowing an attacker to manipulate the parsing logic through the specific TAG sequences. This boundary error creates a condition where the software attempts to write data beyond the allocated memory boundaries, resulting in memory corruption that can lead to arbitrary code execution or application crashes. The vulnerability operates at the intersection of CWE-125, which addresses out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write errors, making it particularly dangerous for image processing applications that handle untrusted input files.
From an operational standpoint, this vulnerability poses significant risks to systems that rely on LibRaw for image processing, particularly in environments where users might encounter untrusted or malicious image files. The impact extends beyond simple application instability to potential remote code execution capabilities, especially when the affected library is used in web applications, digital asset management systems, or image processing pipelines. Attackers can exploit this vulnerability by simply providing a malicious KDC file to any application that utilizes the vulnerable version of LibRaw, making it a particularly attractive target for attackers seeking to compromise systems through image file handling. The ATT&CK framework categorizes this vulnerability under T1203, which covers exploitation for privilege escalation, and T1059, which addresses command and scripting interpreter usage, as the memory corruption can potentially be leveraged to execute malicious code.
The remediation for CVE-2017-6887 requires immediate upgrading to LibRaw version 0.18.2 or later, which includes proper bounds checking and memory validation within the parse_tiff_ifd() function. Organizations should implement comprehensive patch management procedures to ensure all systems utilizing LibRaw are updated promptly. Additionally, input validation should be strengthened at the application level by implementing proper sanitization of image file headers and metadata before processing, along with implementing memory safety measures such as stack canaries and address space layout randomization. Security teams should also consider deploying network monitoring solutions to detect potential exploitation attempts involving malformed image files, while maintaining regular vulnerability assessments to identify other potential boundary error conditions within similar image processing libraries. The fix addresses the underlying CWE-129 issue by implementing proper validation of array indices and memory boundaries, preventing the out-of-bounds memory access that previously enabled the vulnerability.