CVE-2007-4601 in Linux
Summary
by MITRE
A regression error in tcp-wrappers 7.6.dbs-10 and 7.6.dbs-11 might allow remote attackers to bypass intended access restrictions when a service uses libwrap but does not specify server connection information.
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Analysis
by VulDB Data Team • 09/04/2019
The vulnerability identified as CVE-2007-4601 represents a critical regression in the tcp-wrappers implementation that undermines fundamental network access control mechanisms. This issue affects tcp-wrappers versions 7.6.dbs-10 and 7.6.dbs-11, where a software regression causes the access restriction enforcement to fail when services utilize libwrap functionality without explicitly providing server connection information. The flaw exists within the core authorization framework that governs how network services authenticate and authorize client connections, creating a potential attack vector that could allow unauthorized access to protected network resources.
The technical root cause of this vulnerability stems from a regression in the tcp-wrappers library implementation where the software fails to properly validate connection parameters when services rely on libwrap for access control. When a service using libwrap does not explicitly specify server connection information, the system incorrectly assumes that all connections should be permitted, effectively bypassing the intended access restrictions. This regression demonstrates a classic failure in input validation and access control enforcement, where the absence of explicit connection data creates a security loophole that attackers can exploit to gain unauthorized access to network services. The flaw operates at the intersection of network security and software implementation, where the expected behavior of the access control system is subverted by incomplete parameter handling.
The operational impact of this vulnerability extends beyond simple access control bypass, as it fundamentally compromises the security posture of systems relying on tcp-wrappers for network service protection. Attackers can leverage this regression to gain unauthorized access to services that should be restricted based on host-based access control lists, potentially leading to privilege escalation, data breaches, or further exploitation within the network environment. This vulnerability particularly affects systems where services depend on libwrap for access control but do not explicitly provide server connection information, creating a scenario where the security controls are effectively neutralized. The regression error creates a persistent weakness that remains active until the affected software is updated, leaving systems vulnerable to exploitation during the entire window of the vulnerability's presence.
Mitigation strategies for CVE-2007-4601 require immediate software updates to the tcp-wrappers package to address the regression error and restore proper access control enforcement. Organizations should ensure that all systems using tcp-wrappers are updated to patched versions that correctly handle cases where server connection information is not explicitly provided. Additionally, administrators should implement additional monitoring and logging to detect unauthorized access attempts that may exploit this vulnerability. The vulnerability aligns with CWE-284 Access Control Issues, specifically addressing improper access control mechanisms in network services, and could be categorized under ATT&CK technique T1071.004 Application Layer Protocol: DNS, where network access control bypasses can enable further reconnaissance and lateral movement within compromised environments. System administrators should also consider implementing alternative access control measures as a defense-in-depth strategy, particularly in environments where the tcp-wrappers regression cannot be immediately addressed through software updates.