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TCP implementations vulnerable to Denial of Service

Vulnerability Note VU#962459

Original Release Date: 2018-08-06 | Last Revised: 2018-09-14

Overview

The Linux kernel versions 4.9+ and supported versions of FreeBSD are vulnerable to denial of service conditions with low rates of specially modified packets.

Description

CWE-400: Uncontrolled Resource Consumption ('Resource Exhaustion') - CVE-2018-5390

Linux kernel versions 4.9+ can be forced to make very expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet which can lead to a denial of service.

CWE-400: Uncontrolled Resource Consumption ('Resource Exhaustion') - CVE-2018-6922
A TCP data structure in supported versions of FreeBSD (11, 11.1, 11.2, 10, and 10.4) use an inefficient algorithm to reassemble the data.


For both vulnerabilities, an attacker can induce a denial of service condition by sending specially modified packets within ongoing TCP sessions. Maintaining the denial of service condition requires continuous two-way TCP sessions to a reachable open port. Thus, the attacks cannot be performed using spoofed IP addresses.

Impact

An remote attacker may be able to trigger a denial-of-service condition against a system with an available open port.

Solution

Apply a patch
Patches for the Linux kernel are available to address the vulnerability.
Patches for FreeBSD are available to address the vulnerability.

Vendor Information

962459
 

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CVSS Metrics

Group Score Vector
Base 7.1 AV:N/AC:M/Au:N/C:N/I:N/A:C
Temporal 6.4 E:POC/RL:ND/RC:C
Environmental 6.4 CDP:ND/TD:H/CR:ND/IR:ND/AR:ND

References

Acknowledgements

Thanks to Juha-Matti Tilli (Aalto University, Department of Communications and Networking / Nokia Bell Labs) for reporting these vulnerabilities.

This document was written by Trent Novelly.

Other Information

CVE IDs: CVE-2018-5390, CVE-2018-6922
Date Public: 2018-07-23
Date First Published: 2018-08-06
Date Last Updated: 2018-09-14 19:29 UTC
Document Revision: 31

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