CVE-2010-2805 in FreeType
Summary
by MITRE
The FT_Stream_EnterFrame function in base/ftstream.c in FreeType before 2.4.2 does not properly validate certain position values, which allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted font file.
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Analysis
by VulDB Data Team • 09/23/2021
The vulnerability identified as CVE-2010-2805 resides within the FreeType font rendering library, specifically in the FT_Stream_EnterFrame function located in base/ftstream.c. This critical flaw affects FreeType versions prior to 2.4.2 and represents a classic example of improper input validation that can lead to severe security consequences. The vulnerability manifests when the function fails to adequately validate position values during font stream processing, creating a pathway for malicious actors to manipulate the library's behavior through specially crafted font files. The issue falls under the CWE-129 weakness category, which encompasses improper validation of array indices and other input validation errors that can result in buffer overflows or arbitrary code execution.
The technical exploitation of this vulnerability occurs when an attacker constructs a malicious font file that contains malformed position values within the font stream structure. During normal font processing, the FT_Stream_EnterFrame function attempts to advance the stream position by a specified number of bytes, but due to the lack of proper validation, it fails to check whether the calculated position values remain within acceptable bounds. This validation failure allows attackers to manipulate the stream pointer to invalid memory locations, potentially causing the application to crash or, in more sophisticated scenarios, execute arbitrary code. The vulnerability's impact extends beyond simple denial of service since it can be leveraged for remote code execution when the affected FreeType library is used in applications that process untrusted font content. This type of vulnerability aligns with ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain unauthorized access or execute malicious code.
Applications that utilize FreeType for font rendering across various platforms and operating systems are at risk, including web browsers, desktop applications, document viewers, and any software that handles font processing. The vulnerability's remote exploitability means that simply opening or rendering a malicious font file can trigger the attack vector without requiring user interaction beyond the initial font processing. The exploitation typically involves crafting a font file with carefully constructed position values that cause the stream pointer to jump to invalid memory locations, potentially leading to memory corruption and subsequent code execution. Organizations using affected FreeType versions should prioritize immediate patching to address this vulnerability, as the potential for remote code execution makes it particularly dangerous in environments where untrusted font content may be processed. The remediation strategy involves upgrading to FreeType version 2.4.2 or later, which includes proper input validation mechanisms that prevent the manipulation of stream position values and mitigate the risk of both denial of service and arbitrary code execution attacks.