How to Find Altered Files with Yum
In the world of Linux, package management is a crucial aspect of maintaining a stable and secure system. Yum, which stands for Yellowdog Updater, Modified, is one of the most popular package managers used in Red Hat-based distributions. It allows users to install, update, and remove packages from their system. However, there may be instances where files are altered or modified without proper authorization, which can lead to security vulnerabilities. In this article, we will discuss how to find altered files with yum and ensure the integrity of your system.
1. Check the File Integrity
The first step in identifying altered files is to check their integrity. Yum provides a feature called “yum check” that can be used to verify the integrity of installed packages. To do this, open a terminal and run the following command:
“`
sudo yum check
“`
This command will compare the installed packages against their checksums stored in the repositories. If any package is found to be altered, yum will report it.
2. Use Yum-dumpdb and Yum-check
Yum-dumpdb is a tool that generates a database of all installed packages, including their checksums. This database can be used to compare against the current system to identify altered files. To generate the database, run the following command:
“`
sudo yum dumpdb > yum-dumpdb.txt
“`
Now, you can use the yum-check tool to compare the generated database with the current system. Install yum-check using the following command:
“`
sudo yum install yum-check
“`
Once installed, run the following command to compare the database with the current system:
“`
sudo yum-check
“`
This command will output any files that have been altered or modified.
3. Use File Hashing Tools
If yum does not provide sufficient information, you can use file hashing tools like md5sum or sha256sum to compare the checksums of files on your system. First, download the original checksums of the files from a trusted source. Then, compare the checksums of the files on your system using the following command:
“`
md5sum /path/to/file | grep /path/to/trusted/checksum
“`
Replace `/path/to/file` with the actual file path and `/path/to/trusted/checksum` with the path to the trusted checksum file. If the checksums do not match, the file has been altered.
4. Regularly Update Your System
To prevent altered files from compromising your system, it is essential to keep your system up-to-date. Regularly update your packages using yum to ensure that you have the latest security patches and fixes. Run the following command to update your system:
“`
sudo yum update
“`
By following these steps, you can effectively find altered files with yum and maintain the integrity of your Linux system. Always stay vigilant and keep your system secure.
