CVE-2006-2341 in Enterprise Firewall
Summary
by MITRE
The HTTP proxy in Symantec Gateway Security 5000 Series 2.0.1 and 3.0, and Enterprise Firewall 8.0, when NAT is being used, allows remote attackers to determine internal IP addresses by using malformed HTTP requests, as demonstrated using a get request without a space separating the URI.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 05/25/2025
The vulnerability described in CVE-2006-2341 represents a significant information disclosure flaw within Symantec's network security appliances, specifically affecting the Gateway Security 5000 Series and Enterprise Firewall products. This issue manifests when the affected systems operate in Network Address Translation environments, creating a pathway for remote attackers to extract sensitive internal network information through carefully crafted HTTP requests. The flaw exploits the proxy server's insufficient input validation mechanisms, allowing malicious actors to bypass normal request parsing procedures and gain unauthorized visibility into internal network topology. The vulnerability is particularly concerning as it demonstrates how seemingly minor parsing inconsistencies can lead to substantial security implications, exposing the fundamental architecture of protected networks to external threat actors.
The technical implementation of this vulnerability stems from the HTTP proxy's failure to properly validate and sanitize incoming requests when NAT is active. Attackers can exploit this weakness by crafting malformed HTTP GET requests that omit the required space separator between the method and URI components. This particular parsing error occurs within the proxy's request handling logic, where the system attempts to process malformed input without adequate boundary checking or input sanitization. The flaw resides in the proxy's HTTP request parser, which does not enforce proper HTTP protocol compliance during request interpretation. This vulnerability is categorized under CWE-20 as "Improper Input Validation" and demonstrates how protocol violations can be leveraged to extract information from network infrastructure. The specific implementation error occurs in the proxy's request line parsing routine, where insufficient validation allows the system to process malformed requests and inadvertently expose internal IP address information through its response handling or error reporting mechanisms.
The operational impact of this vulnerability extends far beyond simple information disclosure, as it provides attackers with critical reconnaissance data that can be used to map internal network structures and identify potential attack vectors. When an attacker successfully exploits this vulnerability, they can obtain internal IP addresses that would otherwise remain hidden behind the NAT firewall, effectively undermining the network's layered security model. This exposure enables more sophisticated attacks such as targeted exploitation of internal services, advanced persistent threats, or social engineering campaigns that rely on accurate network topology knowledge. The vulnerability's exploitation requires minimal technical expertise, making it particularly dangerous as it can be leveraged by attackers with limited advanced skills. The impact is amplified when considering that many organizations rely on NAT for security purposes, assuming that internal IP addresses remain hidden from external networks. This vulnerability directly violates the principle of least privilege and network segmentation, as it allows external parties to discover internal network addressing schemes that should remain confidential.
Organizations affected by this vulnerability should implement immediate mitigations to protect their network infrastructure and prevent unauthorized information disclosure. The primary recommended action involves applying the vendor-provided security patches and updates that address the HTTP parsing inconsistency in the proxy server implementation. Network administrators should also consider implementing additional monitoring and logging mechanisms to detect unusual HTTP request patterns that might indicate exploitation attempts. The mitigation strategy should include configuring the affected systems to enforce strict HTTP protocol compliance and reject malformed requests before they can be processed by the proxy server. Security teams should also review and update their network access controls to ensure that even if internal IP information is discovered, additional layers of protection remain in place. From an ATT&CK framework perspective, this vulnerability maps to technique T1046 Network Service Scanning and T1082 System Information Discovery, as it enables adversaries to gather network topology information and internal system details. Organizations should conduct thorough network assessments to identify all affected devices and ensure complete remediation across their entire security infrastructure.