CVE-1999-1011 in IIS
Summary
by MITRE
The Remote Data Service (RDS) DataFactory component of Microsoft Data Access Components (MDAC) in IIS 3.x and 4.x exposes unsafe methods, which allows remote attackers to execute arbitrary commands.
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Analysis
by VulDB Data Team • 10/21/2025
The vulnerability identified as CVE-1999-1011 represents a critical security flaw within the Remote Data Service component of Microsoft Data Access Components that affected Internet Information Services versions 3.x and 4.x. This issue stems from the unsafe exposure of methods within the RDS DataFactory component, creating a pathway for remote attackers to execute arbitrary commands on vulnerable systems. The vulnerability exists at the intersection of web server functionality and database access services, where the RDS component was designed to facilitate remote data access but inadvertently created dangerous attack vectors.
The technical flaw manifests through the improper implementation of the RDS DataFactory component which exposes methods that should remain restricted to local system access. Attackers can exploit this vulnerability by crafting specific requests that leverage these exposed methods to execute malicious code on the target server. The vulnerability operates at the application layer and can be exploited through HTTP requests that target the RDS component, making it particularly dangerous as it can be triggered remotely without requiring authentication. This represents a classic example of unsafe method exposure and privilege escalation, classified under CWE-471 which addresses the exposure of functionally equivalent methods.
The operational impact of this vulnerability is severe and far-reaching, as it allows attackers to gain complete control over affected servers. Remote command execution capabilities enable malicious actors to install backdoors, steal sensitive data, modify system configurations, or use compromised systems as launch points for further attacks. The vulnerability affects Microsoft IIS versions 3.x and 4.x, which were widely deployed in enterprise environments during the late 1990s, making the potential attack surface substantial. The impact extends beyond immediate compromise as attackers can use these systems to conduct reconnaissance, establish persistent access, and potentially move laterally within networks.
Security professionals should implement multiple layers of mitigation for this vulnerability, beginning with immediate patching of affected systems to address the underlying flaw in MDAC components. Organizations must also consider network segmentation and firewall rules to restrict access to RDS endpoints, particularly when the component is not required for business operations. The mitigation strategy should include monitoring for suspicious HTTP requests targeting RDS components and implementing strict access controls. According to ATT&CK framework, this vulnerability maps to T1059 for command and script interpreter, as attackers can execute commands through the exposed interface. System administrators should also consider disabling the RDS component entirely when it is not essential for application functionality, as this represents the most effective defense against exploitation. The vulnerability highlights the importance of secure coding practices and proper input validation in web applications, emphasizing that components exposed to remote access must undergo rigorous security review and testing.