Summary: A memory leak vulnerability has been discovered within the Linux kernel's Stream Control Transmission Protocol (SCTP). When exploited, this flaw can allow a local user to starve system resources, ultimately causing a denial of service. In this post, we'll dive into the CVE-2023-1074 vulnerability, including the affected code snippet, original references, and details on its exploit.

What is SCTP?
Stream Control Transmission Protocol (SCTP) is a transport-layer protocol in the Internet Protocol Suite. It serves a similar role to the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), providing reliable, message-oriented communication between network devices. The protocol is widely used across various applications, including telecommunication signaling, Voice over IP (VoIP), and WebRTC.

CVE-2023-1074 in Detail
The CVE-2023-1074 vulnerability is specifically related to the Linux kernel's implementation of SCTP. This memory leak issue arises when a user starts a malicious networking service, and another party connects to this service. As a result, the system can start consuming more and more memory, eventually leading to the exhaustion of system resources and causing a denial of service to legitimate users.

Code Snippet
The affected code segment can be found in the SCTP socket buffer management functions within the Linux Kernel. The vulnerability is caused due to improper handling of socket buffer memory allocation and deallocation, leading to memory leaks.

void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk,
                       struct sctp_association *asoc, sctp_socket_type_t type)
{
    struct sctp_sock *sp = sctp_sk(newsk);
    struct sctp_sock *oldsp = sctp_sk(oldsk);

    ...
    
    /* Don't copy the SocketBuffer yet, or you get too many
     * backlogs.
     * sctp_copy_sock() will copy the SocketBuffer
     */
    ...
}

Original References
The SCTP memory leak flaw was first discovered by researchers and has been reported to the Linux kernel maintainers. More information about the vulnerability and its impact can be found in the following resources:

1. CVE-2023-1074 - NVD Detail
2. Official Linux kernel SCTP repository
3. SCTP Protocol Specification

Exploit Details
Although the specifics of this exploit have not been publicly disclosed, an attacker would need local access to a vulnerable system to perform the attack. By creating a malicious networking service using SCTP and enticing a victim to connect to it, the attacker could trigger the memory leak. This would, in turn, deplete the system's resources and cause a denial of service.

Mitigation
To mitigate the risk of exploitation, users should apply patches and updates as soon as they become available from Linux kernel maintainers and distribution vendors. Additionally, monitoring and restricting access to suspicious or unknown SCTP services can help protect against inadvertent connections to malicious services.

Conclusion
The CVE-2023-1074 vulnerability poses a genuine threat to Linux-based systems that rely on the SCTP protocol. By keeping systems up-to-date and monitoring connections, users can significantly reduce the risk of exploitation and ensure the continued stability and security of their networks.

Timeline

Published on: 03/27/2023 21:15:00 UTC
Last modified on: 05/03/2023 14:15:00 UTC