CVE-2005-3481 in IOS
Summary
by MITRE
Cisco IOS 12.0 to 12.4 might allow remote attackers to execute arbitrary code via a heap-based buffer overflow in system timers. NOTE: this issue does not correspond to a specific vulnerability, rather a general weakness that only increases the feasibility of exploitation of any vulnerabilities that might exist. Such design-level weaknesses normally are not included in CVE, so perhaps this issue should be REJECTed.
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability described in CVE-2005-3481 represents a fundamental design weakness within Cisco IOS versions 12.0 through 12.4 that affects system timer functionality. This heap-based buffer overflow condition exists at the core of the operating system's memory management mechanisms, creating a potential exploitation vector that could be leveraged by remote attackers to execute arbitrary code on affected devices. The issue is classified as a general weakness rather than a specific vulnerability, indicating that it serves as an enabling condition that makes existing or future vulnerabilities more exploitable rather than being a standalone security flaw.
The technical flaw manifests in the way Cisco IOS handles heap memory allocation during system timer operations, where insufficient bounds checking allows malicious input to overwrite adjacent memory locations. This heap-based buffer overflow occurs when the system processes timer-related data structures, potentially corrupting critical memory areas that contain executable code or control information. The vulnerability operates at a low level within the operating system's memory management subsystem, making it particularly dangerous as it can affect core system functions and potentially provide attackers with elevated privileges or complete system compromise.
From an operational impact perspective, this design weakness significantly increases the attack surface for Cisco IOS devices running vulnerable versions. The remote execution capability means that attackers need not have physical access or local credentials to exploit the system, making it particularly concerning for network infrastructure devices that are often exposed to external threats. The vulnerability's nature as a general weakness means that it could compound the effects of other existing vulnerabilities, creating a more dangerous environment for exploitation. Organizations running affected Cisco IOS versions face increased risk of successful attacks that could result in complete network compromise, data exfiltration, or service disruption.
Security professionals should consider this vulnerability as a critical design flaw that requires immediate attention through proper system updates and patches. The recommended mitigation strategy involves upgrading to Cisco IOS versions that address this heap management issue, as well as implementing network segmentation and monitoring to detect potential exploitation attempts. This weakness aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a design-level issue that could enable techniques described in the ATT&CK framework under privilege escalation and execution tactics. Organizations should also implement proper input validation and memory management practices to reduce the impact of similar vulnerabilities that may emerge in the future. The vulnerability's classification as a general weakness rather than a specific CVE indicates that it serves as a foundational issue that requires architectural review and remediation rather than simple patching approaches.