CVE-2001-1218 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer for Unix 5.0SP1 allows local users to possibly cause a denial of service (crash) in CDE or the X server on Solaris 2.6 by rapidly scrolling Chinese characters or maximizing the window.
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Analysis
by VulDB Data Team • 04/07/2017
This vulnerability affects Microsoft Internet Explorer version 5.0 Service Pack 1 running on Unix systems with Solaris 2.6 operating environment. The flaw manifests when the browser encounters rapid scrolling of Chinese characters or window maximization operations, potentially leading to system instability and service disruption. The vulnerability stems from improper handling of Unicode character rendering within the browser's display engine, particularly when processing complex Asian character sets that require extensive memory management and rendering calculations. The issue represents a classic buffer manipulation problem where the system fails to properly validate character sequence lengths during display operations, creating conditions that can overwhelm memory allocation routines.
The technical implementation of this vulnerability involves the interaction between the browser's rendering subsystem and the underlying X Window System graphics framework. When Chinese characters are processed, the system must manage multi-byte character encoding and complex glyph rendering operations that require significant computational resources. Rapid scrolling operations compound this issue by generating high-frequency rendering requests that exceed the system's capacity to process them safely. The X server and CDE (Common Desktop Environment) components become overloaded with malformed rendering instructions, leading to memory corruption or resource exhaustion that ultimately results in system crashes or complete service denial. This vulnerability aligns with CWE-121 which describes stack-based buffer overflow conditions and CWE-122 which covers heap-based buffer overflow scenarios, though the specific manifestation occurs at the application rendering layer rather than in traditional memory management functions.
The operational impact of CVE-2001-1218 extends beyond simple service disruption to potentially compromise the entire desktop environment on affected Solaris systems. When the X server crashes, users lose access to graphical interfaces and must restart their desktop sessions, causing productivity losses and potential data loss. The vulnerability affects systems running Microsoft Internet Explorer for Unix in enterprise environments where Chinese language support is required, particularly in multinational organizations with operations in Asia. Attackers could exploit this weakness systematically by creating web pages designed to trigger the crash conditions through automated scrolling or window manipulation, making it a viable vector for DoS attacks against targeted systems. The vulnerability demonstrates how seemingly benign user interface operations can be weaponized to create system-level instability.
Mitigation strategies for this vulnerability should focus on immediate system hardening and application-level controls. Organizations should apply Microsoft's security patches for Internet Explorer for Unix as soon as available, while also implementing network-level controls to restrict access to potentially malicious web content. System administrators should consider disabling or limiting Chinese character rendering capabilities in the browser configuration where possible, and implement monitoring solutions to detect abnormal X server behavior patterns. The ATT&CK framework categorizes this vulnerability under privilege escalation and denial of service tactics, as it allows local users to compromise system availability through application-level manipulation. Network segmentation and web proxy filtering can help prevent exploitation by limiting direct access to vulnerable systems, while regular system updates and security assessments ensure that similar vulnerabilities are identified and addressed proactively. Additionally, implementing proper input validation and character set handling in web applications can reduce the risk of similar issues in other components of the system infrastructure.