Password spraying: How five months of silence went undetected
Year of occurrence: 2019The attack Password spraying against employee accounts
Attackers used a password spraying campaign to target a well-known cloud computing company's employee accounts, repeatedly attempting a small set of common passwords across many usernames to avoid account lockouts.
Once a single weak password was successfully guessed, the intruders gained entry into the company's internal network and maintained intermittent access for nearly five months, silently exfiltrating personal and financial data.
Severity High
Password spraying remains one of the most common and successful methods for breaching large enterprises.
Because it uses valid credentials and low-volume attempts, most organizations fail to detect it until data has already been stolen or internal systems have been compromised.
How it impacted the organization
Password spraying can:
Initial foothold
Gave attackers initial foothold into corporate networks with legitimate credentials.
MFA bypass
Enabled them to bypass MFA if legacy protocols or unprotected services were exposed.
Long-term persistence
Enabled long-term persistence if the compromised account is rarely monitored.
Data access
Provided access to internal business documents and sensitive employee data.
Undetected operation
With one weak password acting as the entry point, attackers operated undetected for months, as they did in the breach.
With ADAudit Plus in place, organizations can
- Use the dedicated Password Spray report powered by Events 4625, 4771, and 4776 to instantly flag repeated failures across users with short-interval spikes.
- Receive real-time alerts when a successful logon followed multiple failures from the same IP or device.
- Trace the compromised account and every logon tied to it, including unusual endpoints or odd login times.
- Correlate authentication activity with file access to show which internal documents were viewed or exfiltrated.
Outcome
With ADAudit Plus the spraying attempts and subsequent account compromise would have been visible in real time, enabling the company to respond immediately instead of months later.
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