CVE-2001-0376 in Tele2
Summary
by MITRE
SonicWALL Tele2 and SOHO firewalls with 6.0.0.0 firmware using IPSEC with IKE pre-shared keys do not allow for the use of full 128 byte IKE pre-shared keys, which is the intended design of the IKE pre-shared key, and only support 48 byte keys. This allows a remote attacker to brute force attack the pre-shared keys with significantly less resources than if the full 128 byte IKE pre-shared keys were used.
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Analysis
by VulDB Data Team • 04/08/2019
The vulnerability identified as CVE-2001-0376 affects SonicWALL Tele2 and SOHO firewalls running firmware version 6.0.0.0, specifically when implementing IPSEC with IKE pre-shared keys. This represents a significant security weakness that undermines the intended cryptographic strength of the authentication mechanism. The flaw lies in the firmware's restriction of pre-shared key lengths to 48 bytes instead of the standard 128-byte implementation that aligns with IKE protocol specifications and cryptographic best practices. This design limitation directly violates the expected security parameters for IPSEC implementations and creates an exploitable weakness in the authentication framework.
The technical implementation flaw stems from the firmware's hardcoded limitation on pre-shared key sizes, which prevents the utilization of the full cryptographic strength that IKE pre-shared keys are designed to provide. According to the Common Weakness Enumeration framework, this vulnerability maps to CWE-326, which addresses inadequate encryption strength, and CWE-310, which covers cryptographic weaknesses in key management. The restriction to 48-byte keys instead of the full 128-byte specification reduces the effective entropy of the authentication mechanism, making it significantly more susceptible to brute force attacks. This weakness operates at the protocol level within the IPSEC IKE implementation, specifically affecting the key exchange process where pre-shared keys are utilized for authentication between network devices.
The operational impact of this vulnerability is substantial, as it enables remote attackers to conduct more efficient brute force attacks against the pre-shared keys. With only 48 bytes of key material instead of the full 128 bytes, the search space for attackers is dramatically reduced, potentially decreasing attack time from years to mere hours or days depending on computational resources. This vulnerability particularly affects organizations relying on SonicWALL firewalls for network security, as it undermines the fundamental security model of IPSEC-based VPN connections. The attack surface expands beyond simple network access to include potential man-in-the-middle scenarios where attackers can exploit the reduced key strength to gain unauthorized access to protected network segments. According to ATT&CK framework categorization, this vulnerability maps to T1566, which covers credential harvesting through social engineering, and T1071, which addresses application layer protocol usage for communication.
The mitigation strategies for this vulnerability primarily involve firmware updates from SonicWALL to address the key length limitation. Organizations should immediately implement the available firmware patches that restore support for full 128-byte pre-shared keys. Additionally, network administrators should consider implementing alternative authentication mechanisms such as digital certificates instead of pre-shared keys where possible, as this provides stronger authentication and eliminates the key length limitation issue entirely. Network segmentation and access controls should be enhanced to limit the potential impact of any successful exploitation attempts. Regular security assessments should be conducted to ensure that all network devices maintain updated firmware versions that comply with current cryptographic standards and security requirements. The vulnerability demonstrates the critical importance of maintaining up-to-date security implementations and highlights the risks associated with legacy systems that may not properly implement industry-standard cryptographic protocols.