CVE-2016-1624 in Chrome
Summary
by MITRE
Integer underflow in the ProcessCommandsInternal function in dec/decode.c in Brotli, as used in Google Chrome before 48.0.2564.109, allows remote attackers to cause a denial of service (buffer overflow) or possibly have unspecified other impact via crafted data with brotli compression.
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Analysis
by VulDB Data Team • 07/08/2022
The vulnerability CVE-2016-1624 represents a critical integer underflow condition within the Brotli compression library implementation in Google Chrome's web browser. This flaw exists in the ProcessCommandsInternal function located in dec/decode.c file of the Brotli library, which is responsible for decompressing brotli-compressed data streams. The vulnerability specifically affects Chrome versions prior to 48.0.2564.109, making it a significant concern for users running outdated browser versions.
The technical nature of this vulnerability stems from improper handling of integer arithmetic during the decompression process. When processing crafted brotli-compressed data, the integer underflow occurs during calculations involving buffer sizes and offsets, leading to incorrect memory management operations. This condition creates a scenario where the decompression routine attempts to access memory regions beyond the allocated buffer boundaries, resulting in either a buffer overflow condition or other unspecified security impacts. The vulnerability is classified under CWE-191 as an Integer Underflow (Wrap or Wraparound) and aligns with ATT&CK technique T1203 for Exploitation for Execution through malicious data processing.
The operational impact of this vulnerability extends beyond simple denial of service, as it potentially enables remote code execution or arbitrary code manipulation. Attackers can craft malicious brotli-compressed data streams that, when processed by the vulnerable Chrome browser, trigger the integer underflow condition. This could allow adversaries to execute arbitrary code on affected systems with the privileges of the browser process, effectively compromising user systems. The vulnerability is particularly dangerous because brotli compression is increasingly used in web applications and services, making it a common attack vector through web-based delivery mechanisms.
Mitigation strategies for CVE-2016-1624 require immediate browser updates to Chrome version 48.0.2564.109 or later, which includes the necessary patches to address the integer underflow condition. Organizations should implement comprehensive patch management procedures to ensure all affected systems are updated promptly. Additional protective measures include network-based filtering of brotli-compressed content when possible, implementing web application firewalls, and monitoring for suspicious decompression activities. Security teams should also consider deploying intrusion detection systems that can identify patterns associated with exploitation attempts targeting this vulnerability, as the attack surface extends to any web application utilizing brotli compression without proper input validation. The vulnerability demonstrates the importance of rigorous input validation and integer arithmetic safety in compression libraries, particularly those integrated into widely-used applications like web browsers.