CVE-2016-1637 in Chrome
Summary
by MITRE
The SkATan2_255 function in effects/gradients/SkSweepGradient.cpp in Skia, as used in Google Chrome before 49.0.2623.75, mishandles arctangent calculations, which allows remote attackers to obtain sensitive information via a crafted web site.
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Analysis
by VulDB Data Team • 07/09/2022
The vulnerability identified as CVE-2016-1637 resides within the Skia graphics library, specifically in the SkSweepGradient.cpp file where the SkATan2_255 function performs arctangent calculations. This flaw affects Google Chrome versions prior to 49.0.2623.75 and represents a critical information disclosure vulnerability that can be exploited through malicious web content. The issue stems from improper handling of mathematical computations in gradient rendering operations, creating a pathway for remote attackers to extract sensitive data from affected systems.
The technical implementation of this vulnerability involves the SkATan2_255 function which computes arctangent values for gradient sweep operations in the Skia graphics library. When processing crafted web content that utilizes complex gradient effects, the function fails to properly handle edge cases in its mathematical calculations, leading to information leakage through side-channel attacks. This particular flaw demonstrates a classic example of improper arithmetic handling that can be leveraged to infer sensitive information from memory locations. The vulnerability operates at the intersection of graphics rendering and information security, where mathematical precision errors in computational functions can be exploited to extract data.
From an operational perspective, this vulnerability enables remote attackers to execute information disclosure attacks against users of affected Chrome versions through web-based exploits. The attack vector requires a malicious website to be visited by an unsuspecting user, making it particularly dangerous in phishing scenarios or compromised websites. The impact extends beyond simple data leakage as the information obtained through such side-channel attacks could potentially include memory contents, cryptographic keys, or other sensitive system data that could be used for further exploitation. This vulnerability aligns with attack patterns documented in the attack tree model where information disclosure serves as a foundational step for more sophisticated attacks.
The security implications of CVE-2016-1637 can be analyzed through the lens of CWE-191, which categorizes integer underflow and overflow conditions, and relates to broader principles of secure coding practices. This vulnerability represents a failure in proper mathematical function implementation where the arctangent calculation does not adequately handle boundary conditions, creating a side-channel that can be exploited by attackers. The flaw demonstrates the importance of rigorous testing for edge cases in mathematical functions, particularly those used in graphics rendering where precision is critical. Organizations should consider implementing mitigations including browser updates, network-based protections, and monitoring for suspicious gradient-based web content that could indicate exploitation attempts.
Mitigation strategies for this vulnerability center on immediate browser updates to versions 49.0.2623.75 and later where the Skia library implementation has been corrected. System administrators should prioritize patch management to ensure all affected Chrome installations are updated promptly, as this vulnerability can be exploited without user interaction once a malicious website is accessed. Additional defensive measures include implementing web content filtering solutions that can identify and block suspicious gradient-based content, monitoring network traffic for exploitation attempts, and conducting security awareness training to help users recognize potentially malicious websites. The remediation process should also include verification that the patch has been properly applied and that affected systems are no longer vulnerable to this information disclosure attack vector.