Downloading .debs from untrusted sources

Packages offer a convenient way to distribute software, but this ease of distribution comes with risks. For example, a user might provide a direct download link for a package on a public forum or another untrusted source.

Warning

Security risk

We strongly discourage downloading and installing packages from untrusted sources. Doing so bypasses security protections and can lead to malware infections or system instability.

Lack of security verification

Unlike software from Ubuntu’s official repositories (such as the Ubuntu Archive), which includes packages vetted by the Ubuntu Security team, a package file from an untrusted source likely hasn’t undergone security screening. This lack of verification means that attackers may have modified the software inside the package.

When possible, always source packages from trusted sources rather than untrusted sources.

Potential for malware

Installing a package system-wide requires root privileges, as the package itself is allowed to execute arbitrary code with root privileges during the installation. Therefore, a malicious .deb file, which was either distributed or modified by an attacker, will lead to system compromise if installed.

Whenever running a command with root privileges, always ensure you know what the command is going to do and that the inputs come from trusted sources.

System instability and dependency issues

Software from trusted sources, such as the Ubuntu Archive, is built and tested to work with other packages on your system. In contrast, a package from an unknown or untrusted source might have been built for a different version of Ubuntu or have conflicting dependencies. Installing such a .deb can cause system instability due to these conflicts, which in the worst case can render a system unusable.

To avoid dependency issues and ensure system stability, it’s always best to install packages from trusted sources, like Ubuntu’s official repositories.