CVE-2025-20192 in IOS XE
Summary
by MITRE • 05/07/2025
A vulnerability in the Internet Key Exchange version 1 (IKEv1) implementation of Cisco IOS XE Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. The attacker must have valid IKEv1 VPN credentials to exploit this vulnerability.
This vulnerability is due to improper validation of IKEv1 phase 2 parameters before the IPsec security association creation request is handed off to the hardware cryptographic accelerator of an affected device. An attacker could exploit this vulnerability by sending crafted IKEv1 messages to the affected device. A successful exploit could allow the attacker to cause the device to reload.
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Analysis
by VulDB Data Team • 05/07/2025
The vulnerability identified as CVE-2025-20192 represents a critical denial of service weakness within Cisco IOS XE Software's implementation of Internet Key Exchange version 1 protocols. This flaw specifically targets the IKEv1 phase 2 parameter validation mechanisms that occur prior to IPsec security association creation requests being processed by the hardware cryptographic accelerator. The vulnerability requires an authenticated attacker possessing valid IKEv1 VPN credentials to exploit, which limits its immediate impact but does not eliminate the serious operational consequences it presents for network infrastructure security.
The technical root cause of this vulnerability stems from inadequate input validation procedures within the IKEv1 implementation where phase 2 parameters are not sufficiently verified before being forwarded to hardware cryptographic processing units. This validation failure creates a pathway for malformed or crafted IKEv1 messages to be processed without proper sanitization, potentially causing the cryptographic accelerator to encounter unexpected states that trigger system instability. The vulnerability manifests when the system attempts to create IPsec security associations using malformed parameters that the hardware component cannot properly handle, leading to system-wide reload conditions.
From an operational impact perspective, this vulnerability poses significant risks to network availability and business continuity. The ability of an authenticated attacker to force device reloads through carefully crafted IKEv1 messages can disrupt critical network services and potentially create windows of opportunity for more severe attacks. The DoS condition affects the entire network infrastructure that relies on IKEv1 VPN connections, potentially impacting remote access capabilities, site-to-site connections, and overall network communication stability. The reload condition effectively renders the affected device temporarily unavailable, which can cascade into broader network disruption depending on the device's role within the network topology.
Organizations should implement immediate mitigations including updating to patched versions of Cisco IOS XE Software where available, implementing network segmentation to limit access to affected devices, and monitoring for suspicious IKEv1 traffic patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-20, which describes improper input validation as a fundamental weakness in software security implementations. From an ATT&CK framework perspective, this vulnerability could be leveraged as part of a broader attack chain under the T1499 technique for endpoint disruption, potentially enabling attackers to establish persistent access after initial compromise through system reloads that might obscure their activities. Network administrators should also consider implementing additional access controls and monitoring mechanisms specifically targeting IKEv1 protocol traffic to detect and prevent exploitation attempts before they can cause system disruption.