CVE-2001-0537 in IOS
Summary
by MITRE
HTTP server for Cisco IOS 11.3 to 12.2 allows attackers to bypass authentication and execute arbitrary commands, when local authorization is being used, by specifying a high access level in the URL.
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Analysis
by VulDB Data Team • 10/05/2025
This vulnerability exists in Cisco IOS HTTP servers version 11.3 through 12.2 where improper input validation allows authenticated users to escalate privileges and execute arbitrary commands. The flaw specifically affects systems utilizing local authorization mechanisms where access control is managed through the HTTP interface rather than traditional command line interfaces. When users specify a high access level within the URL parameters, the system fails to properly validate these inputs against the configured authorization levels, creating a path for privilege escalation attacks.
The technical implementation of this vulnerability stems from insufficient sanitization of URL parameters that contain access level specifications. Attackers can manipulate the HTTP request by appending specific access level values to the URL, bypassing the normal authentication checks that should validate user privileges before granting access to administrative functions. This represents a classic input validation flaw that allows attackers to manipulate system behavior through crafted requests. The vulnerability is particularly dangerous because it leverages the HTTP interface to gain elevated privileges without requiring legitimate credentials for higher access levels.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete control over affected Cisco devices. Once authenticated with a lower privilege level, attackers can execute arbitrary commands with administrative rights, potentially leading to complete network compromise. This vulnerability affects network infrastructure devices that rely on local authorization for HTTP management access, making it particularly concerning for enterprise environments where such systems are commonly deployed. The attack vector is relatively simple and can be executed through standard web browser interactions, making it accessible to attackers with minimal technical expertise.
Mitigation strategies should focus on implementing proper input validation and access control mechanisms within the HTTP server implementation. Cisco recommends upgrading to IOS versions that contain patches addressing this vulnerability, as well as implementing network segmentation to limit access to administrative interfaces. Organizations should also consider disabling HTTP management access when possible and relying on more secure protocols such as SSH or HTTPS with proper authentication mechanisms. The vulnerability aligns with CWE-20 Input Validation and CWE-285 Improper Authorization categories, and represents a technique that could be categorized under ATT&CK tactic TA0006 Credential Access and TA0003 Persistence. Network administrators should implement monitoring for unusual URL patterns and access level specifications that could indicate exploitation attempts, particularly when observing requests containing high privilege level parameters.