CVE-2023-52881 Vulnerability Analysis & Exploit Details

CVE-2023-52881
Vulnerability Scoring

Analysis In Progress
Analysis In Progress

Attack Complexity Details

  • Attack Complexity:
    Attack Complexity Analysis In Progress
  • Attack Vector:
    Attack Vector Under Analysis
  • Privileges Required: None
    No authentication is required for exploitation.
  • Scope:
    Impact is confined to the initially vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2023-52881 Details

Status: Awaiting Analysis

Last updated: 🕣 21 Nov 2024, 08:40 UTC
Originally published on: 🕚 29 May 2024, 11:16 UTC

Time between publication and last update: 175 days

CVSS Release:

CVE-2023-52881 Vulnerability Summary

CVE-2023-52881: In the Linux kernel, the following vulnerability has been resolved: tcp: do not accept ACK of bytes we never sent This patch is based on a detailed report and ideas from Yepeng Pan and Christian Rossow. ACK seq validation is currently following RFC 5961 5.2 guidelines: The ACK value is considered acceptable only if it is in the range of ((SND.UNA - MAX.SND.WND) <= SEG.ACK <= SND.NXT). All incoming segments whose ACK value doesn't satisfy the above condition MUST be discarded and an ACK sent back. It needs to be noted that RFC 793 on page 72 (fifth check) says: "If the ACK is a duplicate (SEG.ACK < SND.UNA), it can be ignored. If the ACK acknowledges something not yet sent (SEG.ACK > SND.NXT) then send an ACK, drop the segment, and return". The "ignored" above implies that the processing of the incoming data segment continues, which means the ACK value is treated as acceptable. This mitigation makes the ACK check more stringent since any ACK < SND.UNA wouldn't be accepted, instead only ACKs that are in the range ((SND.UNA - MAX.SND.WND) <= SEG.ACK <= SND.NXT) get through. This can be refined for new (and possibly spoofed) flows, by not accepting ACK for bytes that were never sent. This greatly improves TCP security at a little cost. I added a Fixes: tag to make sure this patch will reach stable trees, even if the 'blamed' patch was adhering to the RFC. tp->bytes_acked was added in linux-4.2 Following packetdrill test (courtesy of Yepeng Pan) shows the issue at hand: 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1024) = 0 // ---------------- Handshake ------------------- // // when window scale is set to 14 the window size can be extended to // 65535 * (2^14) = 1073725440. Linux would accept an ACK packet // with ack number in (Server_ISN+1-1073725440. Server_ISN+1) // ,though this ack number acknowledges some data never // sent by the server. +0 < S 0:0(0) win 65535 <mss 1400,nop,wscale 14> +0 > S. 0:0(0) ack 1 <...> +0 < . 1:1(0) ack 1 win 65535 +0 accept(3, ..., ...) = 4 // For the established connection, we send an ACK packet, // the ack packet uses ack number 1 - 1073725300 + 2^32, // where 2^32 is used to wrap around. // Note: we used 1073725300 instead of 1073725440 to avoid possible // edge cases. // 1 - 1073725300 + 2^32 = 3221241997 // Oops, old kernels happily accept this packet. +0 < . 1:1001(1000) ack 3221241997 win 65535 // After the kernel fix the following will be replaced by a challenge ACK, // and prior malicious frame would be dropped. +0 > . 1:1(0) ack 1001

Assessing the Risk of CVE-2023-52881

Access Complexity Graph

The exploitability of CVE-2023-52881 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2023-52881

No exploitability data is available for CVE-2023-52881.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2023-52881, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2023-52881, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2023-52881 does not compromise confidentiality.
  • Integrity: None
    CVE-2023-52881 does not impact data integrity.
  • Availability: None
    CVE-2023-52881 does not affect system availability.

Exploit Prediction Scoring System (EPSS)

The EPSS score estimates the probability that this vulnerability will be exploited in the near future.

EPSS Score: 0.044% (probability of exploit)

EPSS Percentile: 15.73% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 84.27% of others.

CVE-2023-52881 References

External References

CWE Common Weakness Enumeration

Unknown

Protect Your Infrastructure against CVE-2023-52881: Combat Critical CVE Threats

Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.

Other 5 Recently Published CVEs Vulnerabilities

  • CVE-2024-43107 – Improper Certificate Validation (CWE-295) in the Gallagher Milestone Integration Plugin (MIP) permits unauthenticated messages (e.g. alarm events) ...
  • CVE-2024-41724 – Improper Certificate Validation (CWE-295) in the Gallagher Command Centre SALTO integration allowed an attacker to spoof the SALTO server. Thi...
  • CVE-2025-2133 – A vulnerability classified as problematic was found in ftcms 2.1. Affected by this vulnerability is an unknown functionality of the file /admin/ind...
  • CVE-2025-2132 – A vulnerability classified as critical has been found in ftcms 2.1. Affected is an unknown function of the file /admin/index.php/web/ajax_all_lists...
  • CVE-2025-2131 – A vulnerability was found in dayrui XunRuiCMS up to 4.6.3. It has been rated as problematic. This issue affects some unknown processing of the comp...