CVE-2014-3378 in IOS XR
Summary
by MITRE
tacacsd in Cisco IOS XR 5.1 and earlier allows remote attackers to cause a denial of service (process reload) via a malformed TACACS+ packet, aka Bug ID CSCum00468.
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Analysis
by VulDB Data Team • 06/06/2017
The vulnerability identified as CVE-2014-3378 affects Cisco IOS XR software versions 5.1 and earlier, specifically targeting the tacacsd process responsible for handling TACACS+ authentication services. This issue represents a critical denial of service flaw that can be exploited remotely by malicious actors to disrupt network authentication services. The vulnerability manifests when the system receives malformed TACACS+ packets that are not properly validated or handled by the tacacsd daemon, leading to unexpected process termination and system reload operations.
The technical root cause of this vulnerability lies in inadequate input validation within the TACACS+ packet processing mechanism of Cisco IOS XR. When the system encounters malformed TACACS+ packets containing unexpected data structures or malformed headers, the tacacsd process fails to properly handle these invalid inputs and subsequently crashes, triggering an automatic system reload. This behavior falls under CWE-129 Input Validation, specifically addressing improper validation of input data that leads to system instability. The flaw demonstrates a classic buffer overflow or parsing error scenario where the system does not adequately sanitize incoming network traffic before processing it.
From an operational perspective, this vulnerability poses significant risks to network infrastructure availability and security operations. Organizations relying on Cisco IOS XR for their network authentication services face potential disruption of critical network access controls, as the denial of service can occur without any local access requirements. Attackers can exploit this vulnerability remotely, making it particularly dangerous for network environments where TACACS+ services are exposed to untrusted networks or where the system is accessible from multiple network segments. The impact extends beyond simple service disruption to potentially compromising network security posture, as authentication services may become unavailable during critical network operations or security incidents.
The vulnerability aligns with several ATT&CK techniques including T1499.004 for Network Denial of Service and T1566.002 for Phishing via Service, as attackers can leverage the remote execution capability to disrupt network services. Organizations should implement immediate mitigations including applying the relevant Cisco security patches, implementing network segmentation to limit TACACS+ service exposure, and deploying intrusion detection systems to monitor for malformed TACACS+ traffic patterns. Additionally, network administrators should consider disabling TACACS+ services when not actively required and implement proper access controls to limit which systems can communicate with TACACS+ servers. The vulnerability highlights the importance of proper input validation and robust error handling in network service implementations, particularly for authentication systems that form the foundation of network security infrastructure.