CVE-2008-6998 in chrome
Summary
by MITRE
Stack-based buffer overflow in chrome/common/gfx/url_elider.cc in Google Chrome 0.2.149.27 and other versions before 0.2.149.29 might allow user-assisted remote attackers to execute arbitrary code via a link target (href attribute) with a large number of path elements, which triggers the overflow when the status bar is updated after the user hovers over the link.
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Analysis
by VulDB Data Team • 11/03/2024
The vulnerability described in CVE-2008-6998 represents a critical stack-based buffer overflow within Google Chrome's URL eliding functionality, specifically in the chrome/common/gfx/url_elider.cc file. This flaw existed in Chrome versions prior to 0.2.149.29 and demonstrates how seemingly benign user interface elements can become attack vectors when not properly validated. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which occurs when more data is written to a fixed-length stack buffer than it can accommodate, leading to potential memory corruption and arbitrary code execution.
The technical implementation of this vulnerability exploits the way Chrome handles URL display in the status bar when users hover over hyperlinks. When a user hovers over a link containing an excessive number of path elements in the href attribute, the browser attempts to elide (shorten) the URL for display purposes in the status bar. The URL eliding function fails to properly validate the length of the input path elements, allowing an attacker to craft a malicious hyperlink with an excessive number of path components that exceeds the allocated stack buffer size. This particular implementation follows the ATT&CK technique T1203 by leveraging user interaction through web browsing activities to execute malicious code.
The operational impact of this vulnerability is significant as it requires only user interaction through normal web browsing activities, making it particularly dangerous in phishing attacks or malicious website scenarios. Attackers can construct specially crafted URLs with numerous path elements that, when hovered over by a victim, trigger the buffer overflow condition. The overflow can potentially be exploited to overwrite adjacent stack memory, including return addresses, which could allow remote attackers to execute arbitrary code with the privileges of the victim's browser process. This type of attack falls under the category of user-assisted remote code execution, where the attacker needs the victim to interact with the malicious content for exploitation to succeed.
The mitigation strategy for this vulnerability involves updating to Chrome version 0.2.149.29 or later, which includes proper bounds checking and input validation for URL eliding operations. Security researchers recommend that organizations implement browser update policies to ensure all users maintain current versions of web browsers. Additionally, administrators should consider implementing web filtering solutions that can detect and block suspicious URL patterns, though this represents a secondary defense measure since the vulnerability is primarily a code-level issue requiring proper input validation. The fix implemented by Google addresses the root cause by enforcing proper buffer size limitations and implementing robust input validation for path element counts during URL eliding operations, preventing the stack overflow condition from occurring.