CVE-2016-1681 in Chrome
Summary
by MITRE
Heap-based buffer overflow in the opj_j2k_read_SPCod_SPCoc function in j2k.c in OpenJPEG, as used in PDFium in Google Chrome before 51.0.2704.63, allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted PDF document.
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Analysis
by VulDB Data Team • 08/22/2022
The vulnerability CVE-2016-1681 represents a critical heap-based buffer overflow within the OpenJPEG library implementation, specifically within the opj_j2k_read_SPCod_SPCoc function located in j2k.c. This flaw exists in the PDFium component of Google Chrome prior to version 51.0.2704.63, making it a significant security concern for web browsers that rely on JPEG 2000 image format decoding. The vulnerability stems from insufficient input validation and boundary checking during the parsing of JPEG 2000 codestream parameters, particularly when processing the SPCod and SPCoc markers that define coding parameters for the JPEG 2000 standard. Attackers can exploit this weakness by crafting malicious PDF documents containing specially formatted JPEG 2000 images that trigger the vulnerable code path when the browser attempts to render or process these embedded images.
The technical execution of this vulnerability involves the manipulation of JPEG 2000 codestream structures where the opj_j2k_read_SPCod_SPCoc function fails to properly validate the size of data structures before copying them into fixed-size heap buffers. This insufficient bounds checking allows attackers to write beyond the allocated memory boundaries, potentially corrupting adjacent memory regions and leading to unpredictable behavior. The vulnerability manifests when the PDFium renderer processes a crafted PDF containing a JPEG 2000 image with malformed SPCod or SPCoc marker segments that cause integer overflows or improper memory allocation calculations. The heap-based nature of the overflow means that the memory corruption affects the heap allocator's internal data structures, which can lead to memory corruption, application crashes, or in some cases, arbitrary code execution depending on the specific memory layout and exploitation conditions.
The operational impact of CVE-2016-1681 extends beyond simple denial of service scenarios, as the vulnerability presents potential for more severe consequences including remote code execution and system compromise. When exploited successfully, this vulnerability can cause Google Chrome to crash or behave unpredictably when processing malicious PDF documents, potentially allowing attackers to execute arbitrary code with the privileges of the browser process. The vulnerability affects a wide range of systems since PDFium is integrated into multiple Google products including Chrome, Chrome for Android, and various other applications that utilize the PDF rendering engine. The attack vector is particularly concerning as it requires only the simple act of opening a malicious PDF document, making it a low-effort, high-impact exploit that can be delivered through various channels including email attachments, web downloads, or compromised websites. This vulnerability is classified under CWE-121 as a heap-based buffer overflow and aligns with ATT&CK technique T1203 for exploitation of memory corruption vulnerabilities, making it a significant target for advanced persistent threat actors and automated exploit frameworks.
Mitigation strategies for CVE-2016-1681 primarily focus on immediate patching and updating of affected software components. Users and organizations should prioritize updating Google Chrome to version 51.0.2704.63 or later, which includes the necessary fixes for this vulnerability. Additionally, implementing network-level controls such as PDF file filtering and sandboxing mechanisms can provide additional defense-in-depth layers. Security researchers and organizations should monitor for related vulnerabilities in the OpenJPEG library and other JPEG 2000 implementations that may share similar code patterns or architectural flaws. The vulnerability highlights the importance of proper input validation and memory management practices, particularly when dealing with complex image format parsers and embedded content processing. Organizations should also consider implementing automated vulnerability scanning tools that can detect and alert on potentially malicious PDF files containing JPEG 2000 content, enabling proactive threat hunting and incident response activities. The remediation process should include thorough testing of updated software to ensure that the patch does not introduce regressions in PDF rendering functionality while maintaining the security improvements.