CVE-2004-0699 in VPN-1
Summary
by MITRE
Heap-based buffer overflow in ASN.1 decoding library in Check Point VPN-1 products, when Aggressive Mode IKE is implemented, allows remote attackers to execute arbitrary code by initiating an IKE negotiation and then sending an IKE packet with malformed ASN.1 data.
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Analysis
by VulDB Data Team • 07/12/2025
The vulnerability described in CVE-2004-0699 represents a critical heap-based buffer overflow within the ASN.1 decoding library of Check Point VPN-1 products that specifically manifests when Aggressive Mode IKE is implemented. This flaw resides in the cryptographic protocol handling mechanism that governs secure network communications through virtual private networks. The vulnerability affects the fundamental security infrastructure of network access control systems, where the implementation of Internet Key Exchange protocol creates an exploitable condition that can be leveraged by remote attackers to compromise system integrity and execute malicious code.
The technical implementation of this vulnerability stems from improper bounds checking within the ASN.1 decoding routines that process IKE packets during the aggressive mode negotiation phase. When a remote attacker initiates an IKE negotiation and subsequently transmits a crafted packet containing malformed ASN.1 data structures, the vulnerable library fails to properly validate the size of incoming data before copying it into fixed-size heap buffers. This fundamental flaw in input validation creates a condition where attacker-controlled data can overflow allocated memory regions, potentially overwriting adjacent memory locations including return addresses and function pointers. The heap-based nature of the overflow means that the vulnerability can be exploited to manipulate program execution flow through memory corruption techniques that are commonly classified under CWE-121 heap-based buffer overflow conditions.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise within the targeted network infrastructure. Attackers can leverage this vulnerability to gain unauthorized access to VPN-1 systems, potentially enabling them to establish persistent backdoors, escalate privileges, or conduct further reconnaissance within the network perimeter. The remote exploitation capability eliminates the need for physical access or local network presence, making this vulnerability particularly dangerous for organizations relying on Check Point VPN-1 solutions for secure remote access. The vulnerability affects the core security functionality of the system, potentially allowing attackers to bypass authentication mechanisms and gain administrative control over the VPN gateway, which serves as a critical network access point for remote users and systems.
The exploitation of this vulnerability aligns with tactics documented in the MITRE ATT&CK framework under the execution and privilege escalation domains, where attackers can leverage memory corruption vulnerabilities to achieve arbitrary code execution. The specific implementation of Aggressive Mode IKE within Check Point VPN-1 products creates a predictable attack surface that attackers can target without requiring extensive reconnaissance. Organizations implementing this security solution should consider the vulnerability as part of their broader security posture assessment, particularly in environments where remote access is critical and network segmentation is not adequately implemented. The vulnerability demonstrates the importance of proper input validation and bounds checking in cryptographic libraries, highlighting how even fundamental protocol implementations can contain exploitable conditions when proper security measures are not applied.
Mitigation strategies for CVE-2004-0699 should include immediate patch application from Check Point, implementation of network segmentation to limit exposure, and monitoring for suspicious IKE traffic patterns. Organizations should also consider disabling Aggressive Mode IKE if it is not strictly required, as this mode is particularly susceptible to the described vulnerability. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches and implementing robust input validation mechanisms in network security infrastructure components. Security teams should also conduct comprehensive vulnerability assessments to identify similar issues in other cryptographic libraries and protocol implementations within their network infrastructure, as this type of memory corruption vulnerability remains a persistent threat in network security systems.