CVE-2014-7909 in Chrome
Summary
by MITRE
effects/SkDashPathEffect.cpp in Skia, as used in Google Chrome before 39.0.2171.65, computes a hash key using uninitialized integer values, which might allow remote attackers to cause a denial of service by rendering crafted data.
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Analysis
by VulDB Data Team • 02/25/2022
The vulnerability identified as CVE-2014-7909 resides within the Skia graphics library component that serves as a core rendering engine for Google Chrome browser versions prior to 39.0.2171.65. This issue specifically affects the SkDashPathEffect.cpp file which handles dash pattern rendering for graphical elements. The flaw manifests when the system computes hash keys using uninitialized integer values during the processing of crafted graphical data. This particular implementation error creates a condition where the hash computation becomes unpredictable and potentially unstable, opening avenues for exploitation by malicious actors who can craft specific graphical inputs designed to trigger the vulnerability.
The technical nature of this vulnerability stems from improper initialization of integer variables within the hash key computation routine. When the Skia library processes dash path effects, it relies on hash functions to efficiently manage and retrieve graphical patterns. However, the uninitialized integers introduce random values into the hash calculation process, causing the system to potentially enter unstable states or exhibit undefined behavior. This uninitialized memory access pattern represents a classic software flaw that aligns with CWE-457, which specifically addresses the use of uninitialized variables in programming contexts. The vulnerability's impact is particularly concerning because it operates at the graphics rendering level where malicious inputs can be embedded within web content through various vector mechanisms.
From an operational perspective, this vulnerability enables remote attackers to execute denial of service attacks against systems running affected Chrome versions. The crafted graphical data can be embedded within web pages, images, or other multimedia content that Chrome renders, allowing attackers to trigger the hash computation instability without requiring user interaction beyond visiting malicious websites. The denial of service aspect occurs when the browser becomes unresponsive or crashes due to the unpredictable hash computations, effectively rendering the browser unusable for legitimate users. This vulnerability can be particularly impactful in environments where users frequently access untrusted web content, as it requires no special privileges or complex exploitation techniques to manifest its effects.
The mitigation strategies for CVE-2014-7909 primarily involve updating to Chrome version 39.0.2171.65 or later, which contains the necessary patches to properly initialize the integer variables used in hash computations. Security administrators should prioritize this update across all affected systems, particularly in enterprise environments where browser stability and user productivity are paramount. Additionally, implementing network-based security controls such as web application firewalls and content filtering systems can provide additional layers of protection by blocking access to known malicious domains that might host crafted content designed to exploit this vulnerability. The fix addresses the root cause by ensuring all integer variables are properly initialized before hash computations occur, thereby eliminating the potential for uninitialized memory values to influence the hash key generation process and maintaining the stability of the graphics rendering subsystem. This vulnerability demonstrates the importance of proper memory management and initialization practices in graphics libraries, particularly those handling untrusted input data from web environments, and aligns with ATT&CK technique T1499.004 which covers network denial of service attacks through browser-based exploitation mechanisms.