| Gói / sản phẩm | Phiên bản bị ảnh hưởng | Phiên bản đã vá |
|---|---|---|
| io.netty:netty-common | < 4.1.115.Final | 4.1.115.Final |
| netty | < 4.1.115 | 4.1.115 |
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.
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.
If netty finds this files, it reads them and loads them into memory.
By default :
C:\ and create files within it.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.
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
<img width="519" alt="4" src="https://github.com/user-attachments/assets/39df22a3-462b-4fd0-af9a-aa30077ec08f">
<img width="517" alt="5" src="https://github.com/user-attachments/assets/129dbd50-fc36-4da5-8eb1-582123fb528f">
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.
<img width="449" alt="6" src="https://github.com/user-attachments/assets/f8fe1ed0-1a42-4490-b9ed-dbc9af7804be"> <img width="464" alt="7" src="https://github.com/user-attachments/assets/b34b42bd-4fbd-4170-b93a-d29ba87b88eb"> <img width="532" alt="8" src="https://github.com/user-attachments/assets/0656b3bb-32c6-4ae2-bff7-d93babba08a3">Bạn đang dùng một trong các sản phẩm này? Quét site để biết có đang lộ phiên bản có lỗ hổng không.
Quét site miễn phíThe 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
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 :
Server mode :
somaxconn :