CVE-2006-1857 in Linux
Summary
by MITRE
Buffer overflow in SCTP in Linux kernel before 2.6.16.17 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a malformed HB-ACK chunk.
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Analysis
by VulDB Data Team • 06/23/2019
The vulnerability identified as CVE-2006-1857 represents a critical buffer overflow flaw within the Stream Control Transmission Protocol implementation in the Linux kernel version 2.6.16.17 and earlier. This issue specifically affects the handling of Heartbeat Acknowledgment chunks within the SCTP protocol stack, which is designed to provide reliable message delivery across network connections. The flaw exists in the kernel's network protocol implementation where insufficient bounds checking occurs when processing malformed HB-ACK chunks, creating an exploitable condition that can be leveraged by remote attackers to compromise system stability and potentially gain unauthorized execution privileges.
The technical nature of this vulnerability stems from improper input validation within the SCTP protocol handler, where the kernel fails to properly validate the length and structure of incoming HB-ACK chunks before processing them. This buffer overflow condition occurs when the kernel attempts to copy data from a malformed chunk into a fixed-size buffer without adequate boundary checks, allowing attackers to overwrite adjacent memory locations. The vulnerability maps directly to CWE-121, which describes buffer overflow conditions where insufficient space is allocated for data, and can be classified under CWE-787, representing out-of-bounds write conditions that occur when data is written beyond the bounds of a fixed-length buffer. The attack vector is remote and requires no authentication, making it particularly dangerous as it can be exploited from any network location without requiring prior access to the target system.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it creates potential for arbitrary code execution within the kernel context. When successfully exploited, the buffer overflow can cause the kernel to crash and restart, leading to service disruption, or more critically, allow attackers to execute malicious code with kernel-level privileges. This presents a significant risk to systems running vulnerable kernel versions, as the exploitation could result in complete system compromise, data theft, or persistent backdoor access. The vulnerability affects systems that utilize SCTP protocol for network communications, including those running VoIP services, telecommunication infrastructure, or any application that relies on SCTP for reliable data transmission. The impact is particularly severe in enterprise environments where network infrastructure components may be exposed to untrusted networks, as attackers could leverage this vulnerability to gain unauthorized access to critical systems.
Mitigation strategies for CVE-2006-1857 focus primarily on immediate kernel updates to versions 2.6.16.17 or later, where the buffer overflow has been patched through proper input validation and bounds checking mechanisms. System administrators should prioritize patching all affected systems and verify that the update has been successfully applied. Additional protective measures include implementing network segmentation to limit exposure of systems running SCTP services, configuring firewalls to restrict access to SCTP ports, and monitoring network traffic for suspicious HB-ACK chunk patterns. The vulnerability demonstrates the importance of robust input validation in kernel-level code and highlights the critical need for regular security updates and patch management processes. Organizations should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish incident response procedures to address potential compromise scenarios. This vulnerability aligns with ATT&CK technique T1068, which covers local privilege escalation through kernel exploits, and T1498, covering network denial of service attacks that can be executed remotely without authentication.