CVE-2013-2052 in Openswan
Summary
by MITRE
Buffer overflow in the atodn function in libreswan 3.0 and 3.1, when Opportunistic Encryption is enabled and an RSA key is being used, allows remote attackers to cause a denial of service (pluto IKE daemon crash) and possibly execute arbitrary code via crafted DNS TXT records. NOTE: this might be the same vulnerability as CVE-2013-2053 and CVE-2013-2054.
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Analysis
by VulDB Data Team • 03/25/2019
The vulnerability described in CVE-2013-2052 represents a critical buffer overflow condition within the libreswan IPsec implementation that specifically affects versions 3.0 and 3.1. This flaw manifests in the atodn function which processes DNS TXT records during Opportunistic Encryption operations. The vulnerability becomes exploitable when RSA keys are utilized in the cryptographic operations, creating a dangerous intersection between DNS resolution and IPsec security protocols. The affected component is the pluto IKE daemon which serves as the core daemon responsible for establishing and maintaining IPsec security associations within the libreswan framework.
The technical nature of this vulnerability stems from improper input validation within the atodn function where it processes DNS TXT records without adequate bounds checking. When the system encounters crafted malicious DNS TXT records during Opportunistic Encryption setup, the function fails to properly handle oversized input data, leading to a buffer overflow condition. This overflow occurs in the context of the pluto daemon which operates with elevated privileges necessary for network security operations. The vulnerability operates at the application layer and can be triggered remotely through DNS resolution operations, making it particularly dangerous as it requires no direct network access to the target system. The flaw aligns with CWE-121 which describes stack-based buffer overflow conditions, and CWE-787 which addresses out-of-bounds write operations.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enabling remote code execution. When the pluto daemon crashes due to the buffer overflow, it results in a denial of service condition that disrupts IPsec security services for the affected system. However, the more serious implications arise from the potential for arbitrary code execution, which could allow attackers to gain control of the affected system. This vulnerability is particularly concerning in network security contexts where IPsec is used for secure communications, as it could compromise the entire security infrastructure. The attack vector through DNS TXT records means that an attacker could potentially compromise systems simply by manipulating DNS responses, making this a sophisticated and stealthy attack method.
The exploitation of this vulnerability demonstrates characteristics consistent with ATT&CK technique T1059 which involves command and scripting interpreter usage, and T1499 which covers network disruption. The attack requires knowledge of DNS operations and IPsec protocols to craft the malicious records effectively, though the actual exploitation can occur without direct system access. Mitigation strategies should focus on immediate patching of libreswan to versions that address the buffer overflow in the atodn function. Organizations should also implement DNS security measures including DNSSEC validation and monitoring for anomalous DNS TXT record responses. Network segmentation and access controls can help limit the impact if exploitation occurs, while regular security audits should verify proper input validation in all DNS processing components. The vulnerability highlights the importance of robust input validation in security-critical applications and the need for comprehensive testing of all network-facing components that process external data sources.