CVE-2001-1158 in Firewall-1
Summary
by MITRE
Check Point VPN-1/FireWall-1 4.1 base.def contains a default macro, accept_fw1_rdp, which can allow remote attackers to bypass intended restrictions with forged RDP (internal protocol) headers to UDP port 259 of arbitrary hosts.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability identified as CVE-2001-1158 represents a critical security flaw in Check Point VPN-1/FireWall-1 version 4.1 that specifically targets the handling of Remote Desktop Protocol traffic within the firewall's configuration. This issue stems from the presence of a default macro named accept_fw1_rdp within the base.def configuration file, which creates an unintended pathway for malicious actors to circumvent the intended network access controls. The flaw operates at the network protocol level by exploiting how the firewall processes UDP traffic on port 259, which is typically used for RDP internal protocol communication. The vulnerability's impact extends beyond simple access bypass as it allows attackers to forge RDP headers and establish connections to arbitrary hosts, effectively undermining the firewall's primary security function of controlling network access.
The technical implementation of this vulnerability relies on the firewall's insufficient validation of RDP protocol headers when processing traffic through the accept_fw1_rdp macro. This default configuration macro was designed to facilitate legitimate RDP connections but contains a critical design flaw that permits forged header information to pass through the security controls. The vulnerability specifically targets UDP port 259, which serves as the internal RDP communication port, allowing attackers to manipulate the protocol headers to appear as legitimate traffic while actually establishing unauthorized connections. This represents a classic case of insufficient input validation and protocol handling, where the firewall fails to properly authenticate or verify the legitimacy of RDP header information before allowing traffic to proceed.
From an operational perspective, this vulnerability creates a significant risk for organizations relying on Check Point FireWall-1 4.1 for network security. Attackers can exploit this flaw to gain unauthorized access to systems that would normally be protected by the firewall's access controls, potentially leading to complete network compromise. The ability to forge RDP headers and connect to arbitrary hosts means that malicious actors can bypass network segmentation and access sensitive systems that should only be reachable through controlled pathways. This vulnerability directly impacts the firewall's core security model by allowing attackers to establish connections that should be blocked by default, effectively creating a backdoor that can be used for reconnaissance, lateral movement, and data exfiltration. The impact severity aligns with CWE-284 (Improper Access Control) and CWE-310 (Cryptographic Issues) categories, as the flaw involves both access control bypass and protocol manipulation.
Organizations affected by this vulnerability should immediately implement mitigations including disabling the problematic accept_fw1_rdp macro, updating to patched versions of Check Point FireWall-1, and implementing additional network monitoring to detect unusual RDP traffic patterns on UDP port 259. The remediation process should also involve reviewing all default firewall configurations to identify similar security flaws that may exist in other macros or rule sets. Network administrators should consider implementing stricter protocol validation measures and monitoring for forged RDP headers that could indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and lateral movement, as attackers can use the bypass to access systems they would normally be restricted from reaching. The vulnerability also relates to defense evasion tactics since it allows attackers to circumvent security controls without detection, making it particularly dangerous in environments where traditional network monitoring may not detect the forged traffic patterns.