CVE-2005-1208 in Windows
Summary
by MITRE
Integer overflow in Microsoft Windows 98, 2000, XP SP2 and earlier, and Server 2003 SP1 and earlier allows remote attackers to execute arbitrary code via a crafted compiled Help (.CHM) file with a large size field that triggers a heap-based buffer overflow, as demonstrated using a "ms-its:" URL in Internet Explorer.
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Analysis
by VulDB Data Team • 07/04/2025
The vulnerability described in CVE-2005-1208 represents a critical integer overflow flaw affecting multiple versions of Microsoft Windows operating systems including Windows 98, 2000, XP SP2 and earlier, and Server 2003 SP1 and earlier. This vulnerability specifically targets the handling of compiled Help (.CHM) files within the Windows environment, creating a dangerous condition that can be exploited remotely to execute arbitrary code. The flaw manifests when a maliciously crafted CHM file contains a large size field that triggers a heap-based buffer overflow, demonstrating the severe impact that improper input validation can have on system security. The vulnerability is particularly concerning because it leverages the ms-its: URL scheme within Internet Explorer, which is a legitimate means of accessing help content but becomes a vector for exploitation when combined with malformed CHM files.
The technical implementation of this vulnerability stems from inadequate bounds checking during the processing of CHM file metadata, specifically within the size field of the file structure. When Internet Explorer encounters a crafted CHM file through an ms-its: URL, the application fails to properly validate the size parameter, allowing an attacker to specify an excessively large value that exceeds the allocated buffer space. This integer overflow condition results in a heap-based buffer overflow, where the overflowed data can overwrite adjacent memory locations, potentially including executable code or control structures. The vulnerability operates at the intersection of software design flaws and memory management issues, creating a path for attackers to manipulate program execution flow through carefully crafted input data.
The operational impact of CVE-2005-1208 extends beyond simple code execution to encompass full system compromise potential, particularly given the widespread deployment of affected Windows versions during the mid-2000s. Attackers can leverage this vulnerability to gain unauthorized access to systems, escalate privileges, or deploy additional malware payloads without requiring local system access. The remote exploitation capability makes this vulnerability particularly dangerous in networked environments where users may inadvertently click on malicious links or visit compromised websites. The vulnerability's exploitation is facilitated by the legitimate ms-its: URL scheme, which bypasses many traditional security mechanisms that might block suspicious file downloads, making it difficult for users to distinguish between legitimate help content and maliciously crafted CHM files.
Mitigation strategies for CVE-2005-1208 should focus on both immediate patching and operational security measures to protect systems until comprehensive updates can be deployed. Microsoft released security updates addressing this vulnerability through Windows Update, but organizations should also implement network-level protections such as URL filtering and content validation to prevent access to potentially malicious CHM files. The vulnerability demonstrates the importance of input validation and proper bounds checking in software development, aligning with CWE-190 which categorizes integer overflow conditions as critical security weaknesses. Organizations should also consider implementing application whitelisting policies that restrict execution of CHM files from untrusted sources, as well as regular security assessments to identify and remediate similar vulnerabilities in legacy systems that may not receive ongoing support. This vulnerability serves as a historical example of how seemingly benign features like help file systems can become attack vectors when proper security controls are not implemented.
The ATT&CK framework categorizes this vulnerability under the technique of "Exploitation for Privilege Escalation" and "Command and Scripting Interpreter" due to the remote code execution capabilities and the use of legitimate system components for malicious purposes. The vulnerability also relates to "Initial Access" through malicious links and "Execution" via the ms-its: URL scheme, demonstrating how attackers can leverage trusted system features to bypass security controls. This case study emphasizes the critical importance of maintaining up-to-date security patches and the dangers of legacy system support, as Windows 98 and 2000 reached end-of-life long before this vulnerability was fully addressed, leaving many systems vulnerable to attacks that could have been prevented through proper maintenance and security practices.