CVE-2017-6312 in gdk-pixbuf
Summary
by MITRE
Integer overflow in io-ico.c in gdk-pixbuf allows context-dependent attackers to cause a denial of service (segmentation fault and application crash) via a crafted image entry offset in an ICO file, which triggers an out-of-bounds read, related to compiler optimizations.
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Analysis
by VulDB Data Team • 09/05/2020
The vulnerability described in CVE-2017-6312 represents a critical integer overflow flaw within the gdk-pixbuf library's io-ico.c component that specifically affects the handling of icon files. This issue manifests when processing crafted ICO (Icon) files containing maliciously constructed image entry offsets, creating a scenario where the application encounters an out-of-bounds memory read condition. The flaw exists at the intersection of memory management and compiler optimization behaviors, making it particularly insidious as it can be triggered through seemingly benign image file processing operations.
The technical implementation of this vulnerability stems from improper validation of image entry offsets within ICO file structures. When gdk-pixbuf processes an ICO file, it reads the offset values that specify where individual image entries begin within the file. An integer overflow occurs when these offset values are manipulated to exceed the maximum representable value for the integer type used in the processing logic. This overflow results in a negative or excessively large offset value that, when used to calculate memory addresses, leads to memory access violations. The specific nature of the flaw is categorized under CWE-190 as an integer overflow, which directly maps to the conditions described in the CVE description where compiler optimizations can exacerbate the issue by reordering or modifying operations in ways that expose the underlying vulnerability.
From an operational perspective, this vulnerability creates a significant denial of service condition that can be exploited by context-dependent attackers who craft malicious ICO files. The impact extends beyond simple application crashes to potentially causing segmentation faults that can terminate processes or destabilize entire applications that rely on gdk-pixbuf for image processing. This vulnerability affects any software that utilizes the gdk-pixbuf library for handling icon files, which includes numerous desktop applications, web browsers, and image processing tools across various operating systems. The exploitation requires minimal privileges as attackers only need to provide a malicious ICO file to trigger the vulnerable code path, making it particularly dangerous in environments where users might encounter such files through email attachments, web downloads, or file sharing systems.
The mitigation strategies for CVE-2017-6312 primarily involve updating to patched versions of the gdk-pixbuf library where integer overflow protections have been implemented in the io-ico.c component. Organizations should prioritize patch management to ensure all systems using gdk-pixbuf are updated with the latest security fixes that address the integer overflow conditions in image offset processing. Additionally, implementing input validation measures that sanitize ICO file structures before processing can provide defensive layers against malformed entries. Network-level protections such as content filtering and sandboxing mechanisms can further reduce the risk of exploitation by preventing potentially malicious icon files from reaching vulnerable applications. The vulnerability's relationship to compiler optimizations also suggests that developers should be aware of how optimization levels can affect memory safety and should consider disabling aggressive optimizations for security-critical code paths when necessary. This aligns with ATT&CK framework techniques related to privilege escalation and defense evasion where attackers might leverage such vulnerabilities to disrupt services or gain unauthorized access to systems through application crashes.