CVE-2004-0589 in IOS
Summary
by MITRE
Cisco IOS 11.1(x) through 11.3(x) and 12.0(x) through 12.2(x), when configured for BGP routing, allows remote attackers to cause a denial of service (device reload) via malformed BGP (1) OPEN or (2) UPDATE messages.
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Analysis
by VulDB Data Team • 07/12/2025
Cisco IOS versions 11.1(x) through 11.3(x) and 12.0(x) through 12.2(x) contain a critical vulnerability in their Border Gateway Protocol implementation that enables remote attackers to trigger device reloads through crafted malformed BGP messages. This vulnerability specifically affects devices configured with BGP routing protocols and represents a classic buffer overflow or input validation flaw that can be exploited to cause denial of service conditions. The flaw manifests when the system receives malformed OPEN or UPDATE BGP messages, which are standard components of the BGP protocol used for exchanging routing information between different autonomous systems. These messages contain essential routing data and control information that routers use to make forwarding decisions, making them critical components of network infrastructure operations. When the IOS software fails to properly validate or process these malformed messages, it can lead to unpredictable behavior including system crashes and subsequent device reloads that disrupt network connectivity and availability.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers buffer overflow vulnerabilities in stack-based memory structures. The attack vector operates through the network layer where remote adversaries can inject specially crafted BGP messages that exploit insufficient input validation mechanisms within the IOS BGP implementation. This vulnerability directly impacts the availability aspect of the CIA triad by allowing attackers to cause service disruption through device reloads, effectively rendering network infrastructure inaccessible to legitimate users and potentially causing cascading failures across dependent systems. The operational impact extends beyond simple denial of service as the device reloads can occur repeatedly, leading to sustained network outages that affect business continuity and network reliability. Network administrators may experience significant downtime while troubleshooting and implementing mitigations, particularly in large enterprise or service provider environments where BGP is extensively deployed.
From an adversarial perspective, this vulnerability maps to ATT&CK technique T1499.004, which covers network denial of service attacks through the exploitation of system vulnerabilities. The attack requires minimal privileges and can be executed remotely without authentication, making it particularly dangerous for network infrastructure. The vulnerability affects multiple IOS release lines, indicating it was likely introduced in the BGP implementation and persisted across several software versions, suggesting a fundamental design flaw rather than a simple coding error. Organizations with exposed BGP peers or those that accept BGP connections from external autonomous systems are at risk, as the vulnerability can be exploited through normal BGP communication channels without requiring special access or credentials. Mitigation strategies include implementing BGP message filtering, applying Cisco IOS patches and updates, configuring access control lists to restrict BGP peer relationships, and deploying BGP monitoring tools to detect abnormal message patterns. Network segmentation and redundant BGP configurations can also help reduce the impact of successful exploitation attempts, while regular security assessments and vulnerability scanning should be conducted to identify affected systems and ensure proper patch management processes are in place.