CVE-2014-9675 in Android
Summary
by MITRE
bdf/bdflib.c in FreeType before 2.5.4 identifies property names by only verifying that an initial substring is present, which allows remote attackers to discover heap pointer values and bypass the ASLR protection mechanism via a crafted BDF font.
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Analysis
by VulDB Data Team • 09/30/2022
The vulnerability identified as CVE-2014-9675 resides within the FreeType font rendering library, specifically in the bdf/bdflib.c component that handles Binary Diamond Format font files. This flaw represents a critical security issue that undermines memory protection mechanisms and enables sophisticated exploitation techniques. The vulnerability affects FreeType versions prior to 2.5.4, making it a significant concern for systems relying on this widely-used font rendering library.
The technical flaw stems from an insufficient validation mechanism in the property name identification process within the BDF font parser. When processing crafted BDF font files, the system only verifies that an initial substring matches expected property names rather than performing complete string comparison. This partial validation creates a pathway for attackers to manipulate the parsing logic and extract heap pointer values from memory. The vulnerability operates through a classic information disclosure mechanism where the incomplete verification allows attackers to infer memory layout details that should remain hidden from external observation.
The operational impact of this vulnerability is particularly severe as it directly enables attackers to bypass Address Space Layout Randomization, a fundamental security mitigation designed to prevent memory-based attacks. By discovering heap pointer values, threat actors can gain crucial information about memory layout and potentially exploit this knowledge to craft more effective attacks against systems using vulnerable FreeType versions. This vulnerability affects any application that utilizes FreeType for font rendering, including web browsers, desktop applications, and embedded systems that process BDF font files.
The exploitation of this vulnerability aligns with ATT&CK technique T1059 for privilege escalation through application execution and T1068 for local privilege escalation via memory corruption. From a CWE perspective, this represents a weakness categorized under CWE-20, which deals with improper input validation, and specifically manifests as CWE-125, which involves out-of-bounds read conditions. The vulnerability demonstrates how seemingly minor implementation flaws in parsing logic can create significant security implications that compromise fundamental operating system protections.
Mitigation strategies for CVE-2014-9675 primarily involve upgrading to FreeType version 2.5.4 or later, which includes corrected validation mechanisms for property name identification. System administrators should prioritize patching affected systems and applications that rely on FreeType for font processing. Additionally, organizations should implement monitoring for suspicious BDF font file processing and consider restricting font file uploads in web applications. The fix implemented in FreeType 2.5.4 addresses the core validation issue by ensuring complete string matching rather than partial substring verification, thereby preventing the information disclosure that enabled ASLR bypass attempts.