CVE-2011-4093 in net6
Summary
by MITRE
Integer overflow in inc/server.hpp in libnet6 (aka net6) before 1.3.14 might allow remote attackers to hijack connections and gain privileges as other users by making a large number of connections until the overflow occurs and an ID of another user is provided.
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Analysis
by VulDB Data Team • 03/11/2022
The vulnerability identified as CVE-2011-4093 represents a critical integer overflow flaw within the libnet6 library's server component, specifically in the inc/server.hpp file. This issue affects versions prior to 1.3.14 and creates a significant security risk that can be exploited remotely by attackers to hijack network connections and potentially escalate privileges. The vulnerability stems from improper handling of connection ID assignment mechanisms within the library's networking stack, where integer overflow conditions can lead to unexpected behavior in connection management.
The technical implementation of this flaw involves the library's connection tracking system where sequential connection identifiers are managed using integer variables that can overflow when a large number of connections are established. When the integer counter reaches its maximum value and wraps around to zero, the system may assign an existing connection ID to a new connection request. This creates a scenario where an attacker can establish a substantial number of connections to force this overflow condition, thereby obtaining a connection ID that belongs to another legitimate user session. The underlying cause aligns with CWE-190, which addresses integer overflow conditions that can lead to unexpected behavior in software systems.
From an operational perspective, this vulnerability enables attackers to perform connection hijacking attacks that can result in unauthorized access to network sessions and potential privilege escalation. The remote exploitation capability means that attackers do not require local access or physical presence to exploit this weakness, making it particularly dangerous in networked environments. The impact extends beyond simple connection hijacking as successful exploitation could allow attackers to impersonate legitimate users, access sensitive data, or potentially execute arbitrary code within the context of the targeted application's privileges. This vulnerability directly relates to ATT&CK technique T1071.004 for application layer protocol manipulation and T1068 for local privilege escalation through session hijacking.
The mitigation strategies for this vulnerability primarily involve upgrading to libnet6 version 1.3.14 or later, which includes proper integer overflow protection mechanisms in the connection ID management system. Additionally, system administrators should implement connection rate limiting and monitoring to detect unusual patterns of connection establishment that might indicate exploitation attempts. Network segmentation and access controls can help limit the potential impact of successful exploitation, while regular security audits of network libraries and applications can help identify similar vulnerabilities in other components. The fix typically involves implementing proper bounds checking and overflow detection mechanisms in the integer arithmetic operations that manage connection identifiers, ensuring that the system properly handles edge cases where maximum integer values are approached.