Combo.txt 99%

combo.txt is a plain-text file commonly used to store lists of combined credentials, typically in "email:password" or "username:password" format for bulk import/export between tools.

Brute-force tools like SentryMBA, OpenBullet, or SilverBullet often output successful logins into a file named combo.txt by default. This has become an unofficial convention, making the filename a de facto standard in cracking circles.

Possessing a combo.txt file that contains credentials from a known data breach is legally dangerous in most jurisdictions.

Even if you did not create the file, knowingly storing or using a combo.txt can lead to fines, imprisonment, or both. Security researchers must handle such files in isolated, legal environments (e.g., sandboxed VMs with no network access). combo.txt

While the core structure is simple, combo.txt files can include variations that matter to attackers:

Attackers may also append "valid" or "checked" markers. For instance:

admin@example.com:admin123:valid

Here, :valid indicates that the credential has already been tested against a live service and worked. Even if you did not create the file,

The concept is simple: It is a single, running text file that acts as a "combo" platter for your day. It is part to-do list, part journal, part scratchpad, and part brain dump.

There are no fancy formatting tools. No check boxes (unless you type [ ] yourself). No syncing algorithms that drain your battery. It is just raw text.

As passwordless authentication (WebAuthn, passkeys) and rate-limiting APIs become more common, the effectiveness of credential stuffing is declining. However, combo.txt files will not disappear overnight. Legacy systems, shared accounts (Netflix, Spotify), and poor security hygiene ensure a continued market for combos. Attackers may also append "valid" or "checked" markers

Additionally, attackers are evolving. You now see combo.txt files for:

The format remains, but the content expands.