CVE-2014-7941 in Chrome
Summary
by MITRE
The SelectionOwner::ProcessTarget function in ui/base/x/selection_owner.cc in the UI implementation in Google Chrome before 40.0.2214.91 uses an incorrect data type for a certain length value, which allows remote attackers to cause a denial of service (out-of-bounds read) via crafted X11 data.
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Analysis
by VulDB Data Team • 12/11/2024
The vulnerability identified as CVE-2014-7941 resides within the X11 selection handling mechanism of Google Chrome's user interface implementation, specifically in the SelectionOwner::ProcessTarget function located in ui/base/x/selection_owner.cc. This flaw represents a classic out-of-bounds memory access issue that occurs when processing X11 clipboard data, which is a fundamental component of the X Window System used in Unix-like operating systems. The vulnerability manifests when Chrome processes selection data received from X11 servers, where the application incorrectly interprets a length parameter, leading to memory access violations.
The technical root cause of this vulnerability stems from a type confusion error where an unsigned integer value intended to represent data length is incorrectly treated as a signed integer or vice versa, creating a scenario where malicious X11 data can trigger memory access beyond allocated boundaries. This type mismatch occurs during the processing of clipboard selections, where Chrome attempts to handle data received from X11 servers that may contain crafted payloads designed to exploit this specific type handling error. The flaw is classified under CWE-129 as an "Improper Validation of Array Index" and can be categorized under ATT&CK technique T1059.007 for execution through command and scripting interpreter, though in this case the attack vector is more specifically related to memory corruption through X11 protocol manipulation.
The operational impact of this vulnerability allows remote attackers to execute a denial of service attack against Chrome browsers running versions prior to 40.0.2214.91. When exploited, the out-of-bounds read condition can cause Chrome to crash or behave unpredictably, effectively rendering the browser unusable for the affected user. This vulnerability is particularly concerning because it operates at the UI layer of the browser, meaning that simply interacting with malicious X11 data or visiting a compromised website that triggers clipboard operations could lead to exploitation. The attack requires minimal user interaction and can be delivered through various means including malicious websites, X11 servers, or other applications that interact with the X11 clipboard system.
Mitigation strategies for CVE-2014-7941 primarily involve updating to Google Chrome version 40.0.2214.91 or later, which contains the patched implementation of the SelectionOwner::ProcessTarget function with proper type handling for length parameters. System administrators should also consider implementing X11 access controls and monitoring for unusual clipboard activity, particularly in environments where untrusted X11 servers might be present. The fix implemented by Google addresses the core type confusion issue by ensuring proper validation of length values before memory operations are performed, preventing the out-of-bounds read condition that previously allowed attackers to cause denial of service. Organizations should prioritize patching this vulnerability as part of their regular security maintenance procedures, especially in environments where Chrome browsers are used in conjunction with potentially untrusted X11 applications or services.