CVE-2008-1034 in Mac OS X
Summary
by MITRE
Integer underflow in Help Viewer in Apple Mac OS X before 10.5 allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted help:topic URL that triggers a buffer overflow.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/29/2025
The vulnerability described in CVE-2008-1034 represents a critical integer underflow condition within Apple Mac OS X Help Viewer component prior to version 10.5. This flaw exists in the handling of help:topic URLs and demonstrates a classic software security weakness that can be exploited to gain unauthorized system access or disrupt normal operations. The issue stems from improper input validation and arithmetic handling within the help viewer application, creating a pathway for malicious actors to manipulate memory allocation processes.
The technical implementation of this vulnerability involves an integer underflow condition that occurs when processing specially crafted help:topic URLs. When the Help Viewer encounters such malformed input, it fails to properly validate the integer values used for buffer allocation, leading to an underflow scenario. This underflow causes the application to allocate insufficient memory or incorrectly calculate buffer boundaries, ultimately resulting in a buffer overflow condition. The CWE-190 classification applies here as this represents an integer overflow/underflow vulnerability that leads to memory corruption.
From an operational perspective, this vulnerability presents significant risk to Mac OS X users as it allows remote code execution capabilities through web-based attacks. Attackers can craft malicious help:topic URLs that, when processed by the vulnerable Help Viewer, trigger the integer underflow and subsequent buffer overflow. The impact extends beyond simple code execution to include potential denial of service conditions where legitimate applications may crash or become unresponsive. This vulnerability is particularly dangerous because it can be triggered through web browsing activities without requiring user interaction beyond visiting malicious websites.
The attack surface for this vulnerability is broad as the Help Viewer component is integrated into the operating system and can be invoked through various means including web browsers, email clients, and other applications that utilize help system functionality. The ATT&CK framework categorizes this as a privilege escalation technique through application execution, as successful exploitation could allow attackers to execute arbitrary code with the privileges of the Help Viewer process. The vulnerability's remote exploitability makes it particularly concerning for enterprise environments where users may inadvertently access malicious content.
Mitigation strategies for this vulnerability include immediate installation of Apple's security patches and updates to Mac OS X version 10.5 or later, which contain the necessary fixes for the integer underflow condition. System administrators should also implement network-level protections such as URL filtering and web application firewalls to prevent access to known malicious help:topic URLs. Additional protective measures include disabling help system functionality where possible, implementing user education programs to avoid visiting untrusted websites, and monitoring system logs for unusual Help Viewer activity. Organizations should also consider implementing automated patch management systems to ensure all Mac systems receive security updates promptly. The vulnerability highlights the importance of proper input validation and integer arithmetic handling in preventing memory corruption exploits that can lead to complete system compromise.