CVE-1999-1183 in IRIX
Summary
by MITRE
System Manager sysmgr GUI in SGI IRIX 6.4 and 6.3 allows remote attackers to execute commands by providing a trojan horse (1) runtask or (2) runexec descriptor file, which is used to execute a System Manager Task when the user's Mailcap entry supports the x-sgi-task or x-sgi-exec type.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability described in CVE-1999-1183 represents a critical command execution flaw within the System Manager graphical user interface of SGI IRIX operating systems version 6.3 and 6.4. This security weakness stems from improper validation of system descriptors and mailcap configuration entries that govern how the system handles specific file types. The vulnerability specifically targets the interaction between the System Manager's GUI and the mailcap mechanism, which is designed to associate file types with appropriate applications for handling them. Attackers can exploit this flaw by crafting malicious descriptor files that appear legitimate to the system's task execution framework, thereby enabling unauthorized command execution on vulnerable systems.
The technical implementation of this vulnerability leverages the trust relationship between the System Manager GUI and the mailcap configuration system. When a user's mailcap entry supports the x-sgi-task or x-sgi-exec MIME types, the system automatically attempts to execute tasks or commands associated with these descriptors. The flaw occurs because the system does not properly validate the source or integrity of these descriptor files, allowing attackers to place malicious runtask or runexec files in locations where they will be processed automatically. This creates a privilege escalation scenario where remote attackers can execute arbitrary commands with the privileges of the user who processes the malicious descriptor, potentially leading to complete system compromise.
The operational impact of this vulnerability extends beyond simple command execution to encompass full system compromise capabilities. Since the attack vector involves remote exploitation through crafted descriptor files, attackers can potentially gain persistent access to systems without requiring direct network access or authentication. The vulnerability affects the core System Manager functionality, which is typically used for system administration tasks, making it particularly dangerous as it could allow attackers to perform administrative operations, modify system configurations, or establish backdoors. This vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-78 (Improper Neutralization of Special Elements used in OS Command) categories, representing both path traversal and command injection weaknesses.
Mitigation strategies for this vulnerability require a multi-layered approach focusing on both system configuration and administrative controls. Organizations should immediately disable or restrict the x-sgi-task and x-sgi-exec MIME types in mailcap configurations to prevent automatic execution of potentially malicious tasks. System administrators should implement strict file access controls and validate all descriptor files before execution, particularly those located in user-accessible directories. The implementation of proper input validation and source authentication mechanisms within the mailcap processing framework would address the root cause of this vulnerability. Additionally, following the ATT&CK framework's T1059.007 (Command and Scripting Interpreter: PowerShell) and T1546.001 (Event Triggered Execution: Registry Run Keys) techniques, organizations should monitor for suspicious execution patterns and implement network segmentation to limit the potential impact of successful exploitation attempts. Regular system updates and security patches should be applied to address known vulnerabilities in system management interfaces, while security awareness training can help prevent users from inadvertently executing malicious descriptor files.