CVE-2010-1837 in Mac OS X
Summary
by MITRE
CoreText in Apple Mac OS X 10.5.8 and 10.6.x before 10.6.5 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted font in a PDF document.
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Analysis
by VulDB Data Team • 10/05/2021
The vulnerability identified as CVE-2010-1837 resides within Apple Mac OS X's CoreText framework, which serves as a fundamental text rendering engine responsible for processing and displaying typography across the operating system. This critical flaw affects Mac OS X versions 10.5.8 and 10.6.x prior to 10.6.5, where the CoreText component fails to properly validate font data structures when processing PDF documents containing maliciously crafted fonts. The vulnerability represents a classic buffer overflow condition that occurs during font parsing operations, specifically when the system attempts to interpret malformed font metadata within PDF files. This issue falls under the CWE-121 category of Stack-based Buffer Overflow, where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The attack vector leverages PDF documents as a delivery mechanism, making it particularly dangerous in environments where users frequently open PDF files from untrusted sources. When a user opens a malicious PDF containing a specially crafted font, the CoreText framework processes the font data without adequate validation, leading to memory corruption that can be exploited to execute arbitrary code with the privileges of the affected user.
The technical exploitation of this vulnerability occurs through a sophisticated manipulation of font format structures that causes the CoreText engine to allocate insufficient memory for font data processing. Attackers craft font files that contain oversized or malformed data structures which, when processed by the vulnerable CoreText component, trigger memory corruption patterns that can be leveraged for code execution. The memory corruption manifests as heap corruption or stack smashing, depending on how the font data is structured and how the parsing routines handle the malformed input. This type of vulnerability is particularly insidious because it operates within the legitimate text rendering pipeline, making it difficult to detect through traditional security monitoring. The exploit typically requires a carefully constructed PDF document that includes a font file with malicious payload structures, and the attack can result in complete system compromise if successful. The vulnerability's impact extends beyond simple code execution to include potential denial of service conditions where system stability is compromised through memory corruption.
The operational impact of CVE-2010-1837 is substantial across enterprise and individual user environments, particularly given the widespread use of Mac OS X in professional settings where PDF documents are commonly exchanged. Organizations relying on Mac systems for document processing face significant risk from this vulnerability, as it allows remote attackers to gain unauthorized access to systems through seemingly benign PDF files. The vulnerability can be exploited in various attack scenarios including targeted phishing campaigns, where attackers send malicious PDF documents to specific individuals or organizations. The memory corruption aspect of the vulnerability also means that systems could crash or become unstable, leading to denial of service conditions that disrupt business operations. In addition to direct exploitation, the vulnerability creates opportunities for privilege escalation attacks where attackers could potentially gain elevated system privileges through the execution of malicious code. The attack surface is particularly broad since PDF documents are commonly opened by default applications, making the exploitation process relatively simple for threat actors.
Mitigation strategies for CVE-2010-1837 focus primarily on applying the official security patches released by Apple, specifically updating to Mac OS X 10.6.5 or later versions where the vulnerability has been addressed. System administrators should implement immediate patch management procedures to ensure all affected Mac systems receive the necessary updates. Additional protective measures include implementing PDF document filtering and sanitization processes at network boundaries, particularly for incoming documents from untrusted sources. Organizations should consider implementing sandboxing mechanisms that isolate PDF processing activities from core system operations to limit potential damage from successful exploits. Network monitoring should be enhanced to detect unusual PDF document handling patterns or attempts to access malformed font data. Security teams should also consider disabling automatic PDF preview features in web browsers and email clients where possible, reducing the attack surface for this vulnerability. The remediation process should include comprehensive testing of patches in controlled environments before widespread deployment to ensure compatibility with existing applications and workflows. Regular security assessments should verify that all Mac systems have been properly updated and that no instances of the vulnerable CoreText component remain operational within the organization's infrastructure.