CVE-2017-6074 in Communications
Summary
by MITRE
The dccp_rcv_state_process function in net/dccp/input.c in the Linux kernel through 4.9.11 mishandles DCCP_PKT_REQUEST packet data structures in the LISTEN state, which allows local users to obtain root privileges or cause a denial of service (double free) via an application that makes an IPV6_RECVPKTINFO setsockopt system call.
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Analysis
by VulDB Data Team • 12/21/2024
The vulnerability identified as CVE-2017-6074 represents a critical flaw in the Linux kernel's implementation of the Datagram Congestion Control Protocol within the net/dccp/input.c file. This issue affects kernel versions through 4.9.11 and manifests in the improper handling of DCCP_PKT_REQUEST packet data structures while the protocol is in LISTEN state. The flaw specifically arises when an application invokes the IPV6_RECVPKTINFO setsockopt system call, creating a dangerous condition that can be exploited by local users to escalate privileges or disrupt system operations.
The technical mechanism underlying this vulnerability stems from a double free condition that occurs during packet processing in the DCCP protocol implementation. When the dccp_rcv_state_process function encounters a DCCP_PKT_REQUEST packet while the connection is in LISTEN state, it fails to properly validate or manage the memory allocated for packet data structures. This improper memory management creates a scenario where the same memory location can be freed twice, leading to potential arbitrary code execution. The vulnerability is particularly dangerous because it operates within the kernel space, allowing local attackers with minimal privileges to leverage this flaw for privilege escalation to root level access. The specific triggering condition involves the combination of the LISTEN state transition with the IPV6_RECVPKTINFO socket option, which creates a race condition in the packet processing pipeline.
The operational impact of CVE-2017-6074 extends beyond simple privilege escalation to encompass potential system instability and denial of service conditions. Attackers can exploit this vulnerability to cause system crashes through the double free operation, effectively creating a persistent denial of service scenario that could compromise system availability. The vulnerability's local nature means that any user with access to the system can potentially exploit it, making it particularly concerning for multi-user environments where privilege separation is critical. Additionally, the root privilege escalation capability provides attackers with complete system control, enabling them to modify system files, install malicious software, or establish persistent backdoors. This vulnerability directly maps to CWE-415, which describes improper handling of double-free conditions in memory management, and aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' through kernel-level vulnerabilities.
Mitigation strategies for CVE-2017-6074 should prioritize immediate kernel updates to versions that contain the patched implementation of the dccp_rcv_state_process function. System administrators must ensure that all affected Linux systems receive security patches from their respective vendors or apply the official kernel patches that address the double free condition in the DCCP protocol handling. Additionally, implementing network segmentation and limiting the exposure of DCCP services can reduce the attack surface. Monitoring for unusual network traffic patterns or system behavior that might indicate exploitation attempts should be part of the defensive posture. The vulnerability also highlights the importance of kernel security hardening measures such as enabling kernel address space layout randomization and implementing strict privilege controls for socket operations. Organizations should conduct thorough vulnerability assessments to identify systems running affected kernel versions and prioritize remediation efforts based on the criticality of the affected systems within their infrastructure.