Verifying installed RPM packages for tampering with rpm -V

Goal

Use rpm -V to find files that differ from what a package originally installed, as a local integrity check.

Prerequisites

Root access for a complete check (unreadable files show as untestable rather than clean); the RPM database itself intact.

Steps

1. Verify one package:

rpm -V httpd

No output means nothing differs from the database's recorded state for that package. 2. Verify everything installed — slow, since it reads every tracked file on disk:

rpm -Va

3. Narrow to just a package's configuration files:

rpm -Vc httpd

4. Read the output line. rpm's manual page lists the verify options and their single-letter codes: S file size differs, M mode (permissions or type) differs, 5 file digest differs (formerly an MD5 sum), D device number differs, L symlink target differs, U owner differs, G group differs, T mtime differs, P capabilities differ, and ? means a test could not run at all — commonly a missing file or insufficient permission. A trailing c marks a config file.
5. Treat a binary under /usr/bin or /usr/sbin showing 5 and T changed, with no matching entry in rpm -q --changelog or recent dnf history, as worth investigating.
6. Identify which package owns a specific file you're already suspicious of, before checking that whole package:

rpm -qf /usr/sbin/sshd

Expected result

rpm -V on an untouched package returns nothing, aside from expected c-marked config files admins are meant to edit.

Limits and test basis

This compares files against locally stored package metadata captured at install time; an attacker with root can alter the RPM database itself, and a repackaged or resigned RPM defeats the comparison entirely. Use it as a housekeeping and first-look detection aid, not a substitute for a file-integrity tool with an offline-stored baseline or a remote attestation mechanism. Config files intentionally edited by an admin are expected to show 5 and are not by themselves an anomaly.