CVE-2018-6156 in Chrome
Summary
by MITRE
Incorect derivation of a packet length in WebRTC in Google Chrome prior to 68.0.3440.75 allowed a remote attacker to potentially exploit heap corruption via a crafted video file.
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Analysis
by VulDB Data Team • 07/17/2024
The vulnerability identified as CVE-2018-6156 represents a critical heap corruption flaw within the WebRTC implementation of Google Chrome browser versions prior to 68.0.3440.75. This issue stems from an incorrect calculation of packet length during the processing of video content, creating a pathway for remote attackers to execute arbitrary code through maliciously crafted video files. The flaw exists in the WebRTC subsystem responsible for real-time communication and media processing, specifically affecting how the browser handles packet length calculations during video transmission and reception. This vulnerability demonstrates a classic buffer over-read condition where insufficient validation of packet length parameters leads to memory corruption.
The technical implementation of this vulnerability involves the improper handling of packet size calculations within the WebRTC media processing pipeline. When Chrome processes video streams, it must accurately determine the length of incoming packets to properly allocate memory buffers for processing. The incorrect derivation of packet length values allows attackers to manipulate these calculations in such a way that subsequent memory operations exceed allocated buffer boundaries, resulting in heap corruption. This type of vulnerability falls under CWE-129 Input Validation and CWE-787 Out-of-bounds Write, representing a fundamental flaw in memory management and input validation processes. The attack vector requires remote code execution through a crafted video file that triggers the vulnerable code path during normal video processing operations.
The operational impact of CVE-2018-6156 extends beyond simple memory corruption, as it enables remote attackers to potentially execute arbitrary code on affected systems with the privileges of the Chrome browser process. This vulnerability affects users who browse the web and encounter malicious video content, making it particularly dangerous in environments where users may be exposed to untrusted media content through various channels including web pages, email attachments, or malicious websites. The vulnerability's exploitation potential aligns with ATT&CK technique T1203 Exploitation for Client Execution, where attackers leverage browser vulnerabilities to execute malicious code. The affected WebRTC implementation impacts both audio and video communication features, making it a significant threat to real-time communication security. Organizations relying on Chrome for video conferencing, streaming, or other WebRTC-based applications face substantial risk from this vulnerability.
Mitigation strategies for CVE-2018-6156 primarily involve immediate browser updates to Chrome version 68.0.3440.75 or later, which contains the necessary patches to correct the packet length derivation logic. System administrators should also implement network-level protections such as content filtering and web application firewalls to prevent access to known malicious video content. Additional defensive measures include disabling WebRTC functionality in browsers when not required, implementing strict browser sandboxing policies, and monitoring for unusual network traffic patterns that might indicate exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date browser software and implementing comprehensive security monitoring to detect and respond to exploitation attempts. Organizations should also consider deploying security awareness training to educate users about the risks of visiting untrusted websites or downloading content from unknown sources, as these remain common attack vectors for delivering malicious WebRTC content.