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Files by Type

Prohibited files are media, documents, and anything else the README's policy says shouldn't be on the machine. Also credential files: password lists, private keys, and exported hashes sitting in plain text.

Search with PowerShell

Windows Search works from File Explorer (*.mp3 in the search box), but PowerShell searches everywhere in one command:

Get-ChildItem C:\Users -Recurse -Include *.mp3,*.mp4,*.avi,*.mkv,*.mov,*.flac,*.wav,*.wma,*.m4a -ErrorAction SilentlyContinue -Force | Select FullName, Length

-Force includes hidden files, and files get hidden on purpose. -ErrorAction SilentlyContinue skips folders you can't read.

Whole drive, when time allows:

Get-ChildItem C:\ -Recurse -Include *.mp3,*.mp4 -ErrorAction SilentlyContinue -Force | Select FullName

Extensions worth sweeping

Category Extensions
Audio mp3 wav flac aac wma m4a ogg
Video mp4 avi mkv mov wmv flv m4v webm
Images (if policy prohibits personal photos) jpg jpeg png gif bmp
Archives that can hide anything zip rar 7z iso tar gz
Executables and scripts outside Program Files exe msi bat cmd ps1 vbs js jar scr
Credential files *pass* *pwd* *.kdbx *.pem *.ppk *.key *.pfx
Hash dumps and tool output *.txt in odd places, *.pot *.hccapx *.pcap

Search by name pattern too:

Get-ChildItem C:\Users -Recurse -Include *pass*,*pwd*,*secret* -ErrorAction SilentlyContinue -Force | Select FullName

Certificate and key files

Software certificate files (.pfx, .p12) contain a private key and, often, the password to unlock it. Once the certificate is imported they should be deleted (STIG WN11-00-000130). Find them:

Get-ChildItem C:\ -Recurse -Include *.pfx,*.p12 -ErrorAction SilentlyContinue -Force | Select FullName

Read the policy carefully

"No media files" is different from "no music files." A company training video is not a pirated movie. When the README describes a category, delete that category and only that category.

Delete

Remove-Item "C:\Users\bob\Music\track01.mp3"

Or from the search results directly:

Get-ChildItem C:\Users -Recurse -Include *.mp3 -ErrorAction SilentlyContinue -Force | Remove-Item

Look at the list before piping to Remove-Item. There's no undo.

Verify

Re-run the search. Empty output.

Example

README: "Company policy prohibits music and video files on workstations." The sweep finds 40 .mp3 files in C:\Users\bob\Music and C:\Users\Public\Videos\movie.mkv. Delete all of them. It also finds C:\Users\bob\Desktop\passwords.txt. That's not media, but it's a credential file; open it, note what's inside (the passwords in it are compromised and need changing), then delete it.

Next

Malware Persistence