CVE-2001-0815 in Activeperl
Summary
by MITRE
Buffer overflow in PerlIS.dll in Activestate ActivePerl 5.6.1.629 and earlier allows remote attackers to exute arbitrary code via an HTTP request for a long filename that ends in a .pl extension.
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Analysis
by VulDB Data Team • 10/04/2025
The vulnerability identified as CVE-2001-0815 represents a critical buffer overflow flaw within the PerlIS.dll component of Activestate ActivePerl version 5.6.1.629 and earlier installations. This issue specifically manifests when the web server component processes HTTP requests containing excessively long filenames that conclude with the .pl extension, which is commonly associated with perl script files. The flaw resides in the improper handling of input validation within the server-side processing logic, creating an exploitable condition that can be leveraged by remote attackers to execute arbitrary code on the affected system.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The buffer overflow occurs during the parsing of HTTP requests, specifically when the server attempts to process filenames that exceed predetermined memory allocation limits. The PerlIS.dll module responsible for handling perl script execution fails to properly validate the length of incoming filename parameters, allowing malicious actors to craft HTTP requests with deliberately oversized filenames that trigger the overflow condition. This particular implementation flaw demonstrates poor input sanitization practices and inadequate memory management within the web server component of ActivePerl.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with potential system compromise capabilities that can lead to complete control of the affected server. Remote code execution vulnerabilities of this nature are particularly dangerous because they allow attackers to operate without requiring local system access or authentication credentials. Successful exploitation could enable attackers to install backdoors, modify system files, steal sensitive data, or use the compromised server as a launch point for further attacks against internal networks. The vulnerability affects organizations running ActivePerl web server components, particularly those hosting perl scripts or applications that rely on the affected dll module, making it a significant concern for web application security.
Mitigation strategies for CVE-2001-0815 should prioritize immediate patching of affected ActivePerl installations to version 5.6.1.630 or later, which contains the necessary fixes for the buffer overflow condition. Network administrators should implement perimeter defenses including web application firewalls and intrusion detection systems that can identify and block malformed HTTP requests containing excessive filename lengths. Additionally, input validation should be strengthened at multiple layers of the application stack, with proper bounds checking implemented for all filename parameters regardless of their extension. Security monitoring should include detection of unusual HTTP request patterns and length variations that could indicate exploitation attempts. Organizations should also consider implementing principle of least privilege access controls and regular security assessments to identify similar vulnerabilities in other server components that may be susceptible to similar buffer overflow conditions. The remediation efforts should align with ATT&CK framework tactics related to privilege escalation and persistence, ensuring comprehensive protection against exploitation attempts that leverage such memory corruption vulnerabilities.