Password spraying
Trying one common password against many accounts, rather than many passwords against one. Each account sees a single failed attempt, which is below the threshold that would lock it or raise an alert.
Why it matters to you
Per account lockout is the control this technique is designed around, and having it does not help. The signal is horizontal: one password, one source, many usernames, all just under the limit. If your alerting is scoped to a single account it cannot see the attack by construction.
Where we meet it
The password list is not guessed, it is bought. Combolists sorted by locale and by sector circulate for exactly this, which is why the sprayed password often looks oddly specific to the target's country or industry.
Connected terms
Combolist
A recycled email:password list compiled from old breaches and other people's logs, resold in bulk. The fast food of the credential economy: cheap, stale, everywhere.
Credential stuffing
Replaying credentials leaked from one service against every other service, at scale, on the assumption that people reuse passwords. The industrial use for every combolist and log ever sold.
Checker
A tool that tests stolen credentials against a target service in bulk and sorts the live ones from the dead. The industrialized step between a combolist and an account takeover.
Read elsewhere
Where this term stops being vocabulary
Sherlog is where you watch it happen to you
Knowing the word is the cheap half. The platform is the half where the term arrives attached to your domain, with a timestamp and the source it came from.
More from the playbook
Adversary-in-the-middle phishing
A phishing page that proxies the real login instead of imitating it. The victim authenticates against the genuine site through the attacker's server, completes multi-factor as normal, and the attacker keeps the resulting session cookie.
Business Email Compromise (BEC)
Fraud committed from inside a real mailbox: the attacker reads the thread, waits for an invoice and answers it with different bank details. No malware, no attachment, nothing for a scanner to find.
Callback phishing
An email that carries no link and no attachment, only a plausible invoice or subscription notice and a phone number to dispute it. The attack begins when the victim calls, and the person who answers walks them into installing remote access software.
Checker
A tool that tests stolen credentials against a target service in bulk and sorts the live ones from the dead. The industrialized step between a combolist and an account takeover.