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Update dependency io.netty:netty-common to v4.1.115.Final [SECURITY] #887

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@renovate renovate bot commented Nov 13, 2024

This PR contains the following updates:

Package Change Age Adoption Passing Confidence
io.netty:netty-common (source) 4.1.100.Final -> 4.1.115.Final age adoption passing confidence

GitHub Vulnerability Alerts

CVE-2024-47535

Summary

An unsafe reading of environment file could potentially cause a denial of service in Netty.
When loaded on an Windows application, Netty attemps to load a file that does not exist. If an attacker creates such a large file, the Netty application crash.

Details

When the library netty is loaded in a java windows application, the library tries to identify the system environnement in which it is executed.

At this stage, Netty tries to load both /etc/os-release and /usr/lib/os-release even though it is in a Windows environment.

1

If netty finds this files, it reads them and loads them into memory.

By default :

  • The JVM maximum memory size is set to 1 GB,
  • A non-privileged user can create a directory at C:\ and create files within it.
2 3

the source code identified :
https://github.com/netty/netty/blob/4.1/common/src/main/java/io/netty/util/internal/PlatformDependent.java

Despite the implementation of the function normalizeOs() the source code not verify the OS before reading C:\etc\os-release and C:\usr\lib\os-release.

PoC

Create a file larger than 1 GB of data in C:\etc\os-release or C:\usr\lib\os-release on a Windows environnement and start your Netty application.

To observe what the application does with the file, the security analyst used "Process Monitor" from the "Windows SysInternals" suite. (https://learn.microsoft.com/en-us/sysinternals/)

cd C:\etc
fsutil file createnew os-release 3000000000
4 5

The source code used is the Netty website code example : Echo ‐ the very basic client and server.

The vulnerability was tested on the 4.1.112.Final version.

The security analyst tried the same technique for C:\proc\sys\net\core\somaxconn with a lot of values to impact Netty but the only things that works is the "larger than 1 GB file" technique. https://github.com/netty/netty/blob/c0fdb8e9f8f256990e902fcfffbbe10754d0f3dd/common/src/main/java/io/netty/util/NetUtil.java#L186

Impact

By loading the "file larger than 1 GB" into the memory, the Netty library exceeds the JVM memory limit and causes a crash in the java Windows application.

This behaviour occurs 100% of the time in both Server mode and Client mode if the large file exists.

Client mode :

6

Server mode :

7

somaxconn :

8

Severity

  • Attack vector : "Local" because the attacker needs to be on the system where the Netty application is running.
  • Attack complexity : "Low" because the attacker only need to create a massive file (regardless of its contents).
  • Privileges required : "Low" because the attacker requires a user account to exploit the vulnerability.
  • User intercation : "None" because the administrator don't need to accidentally click anywhere to trigger the vulnerability. Furthermore, the exploitation works with defaults windows/AD settings.
  • Scope : "Unchanged" because only Netty is affected by the vulnerability.
  • Confidentiality : "None" because no data is exposed through exploiting the vulnerability.
  • Integrity : "None" because the explotation of the vulnerability does not allow editing, deleting or adding data elsewhere.
  • Availability : "High" because the exploitation of this vulnerability crashes the entire java application.

Configuration

📅 Schedule: Branch creation - "" (UTC), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.


  • If you want to rebase/retry this PR, check this box

This PR was generated by Mend Renovate. View the repository job log.

@renovate renovate bot added the dependencies Pull requests that update a dependency file label Nov 13, 2024
@renovate renovate bot requested a review from astrowq November 13, 2024 01:01
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