CVE-2024-47659 Affecting linux-6.1 package, versions <6.1.119-1~deb11u1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.1% (42nd percentile)

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  • Snyk IDSNYK-DEBIAN11-LINUX61-8600737
  • published2 Jan 2025
  • disclosed9 Oct 2024

Introduced: 9 Oct 2024

CVE-2024-47659  (opens in a new tab)

How to fix?

Upgrade Debian:11 linux-6.1 to version 6.1.119-1~deb11u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.1 package and not the linux-6.1 package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

smack: tcp: ipv4, fix incorrect labeling

Currently, Smack mirrors the label of incoming tcp/ipv4 connections: when a label 'foo' connects to a label 'bar' with tcp/ipv4, 'foo' always gets 'foo' in returned ipv4 packets. So,

  1. returned packets are incorrectly labeled ('foo' instead of 'bar')
  2. 'bar' can write to 'foo' without being authorized to write.

Here is a scenario how to see this:

  • Take two machines, let's call them C and S, with active Smack in the default state (no settings, no rules, no labeled hosts, only builtin labels)

  • At S, add Smack rule 'foo bar w' (labels 'foo' and 'bar' are instantiated at S at this moment)

  • At S, at label 'bar', launch a program that listens for incoming tcp/ipv4 connections

  • From C, at label 'foo', connect to the listener at S. (label 'foo' is instantiated at C at this moment) Connection succeedes and works.

  • Send some data in both directions.

  • Collect network traffic of this connection.

All packets in both directions are labeled with the CIPSO of the label 'foo'. Hence, label 'bar' writes to 'foo' without being authorized, and even without ever being known at C.

If anybody cares: exactly the same happens with DCCP.

This behavior 1st manifested in release 2.6.29.4 (see Fixes below) and it looks unintentional. At least, no explanation was provided.

I changed returned packes label into the 'bar', to bring it into line with the Smack documentation claims.

CVSS Scores

version 3.1