Azure AD Alert Details
Alert ID: AAD-BRUTEFORCE-1110-7842 Alert Time: 2024-02-21 14:15:33 EST Severity: HIGH (88/100) Source: Azure AD Identity Protection Rule: “Password Spray Attack Detected” MITRE ATT&CK: T1110.003 – Brute Force: Password Spraying
Alert Details:
Detection: Multiple failed login attempts followed by success – password spray pattern
Time Window: 14:00 – 14:15 EST Source IP: 185.143.221[.]89 (Bulgaria) Attack Pattern: Password spraying across multiple accounts
Failed Attempts:
14:00:15 – user1@company.com (password: Winter2024!) – FAILED
14:00:30 – user2@company.com (password: Winter2024!) – FAILED
14:00:45 – user3@company.com (password: Winter2024!) – FAILED
14:01:00 – user4@company.com (password: Winter2024!) – FAILED
… (continuing with same password across different users)
Total Attempts: 847 in 15 minutes
Unique users targeted: 847
Same password used: “Winter2024!” (common seasonal password)
Successes: 12 accounts compromised
Failure rate: 98.6% (expected for password spray)
Compromised Accounts:
jsmith@company.com (John Smith – Sales)
kwilson@company.com (Karen Wilson – Marketing)
bturner@company.com (Brian Turner – Finance)
[9 additional accounts – see attachment]
Successful Logins:
14:12:15 – jsmith@company.com from 185.143.221[.]89
14:12:30 – kwilson@company.com from 185.143.221[.]89
14:12:45 – bturner@company.com from 185.143.221[.]89
(others followed same pattern)
Detection Logic:
High volume of failed logins from single IP
Same password used across many accounts
Pattern matches password spraying technique
Successes followed by immediate access
Threat Intelligence:
IP 185.143.221[.]89 known for credential stuffing attacks
Password “Winter2024!” is common seasonal password
Attackers likely obtained list of valid usernames
SOC Investigation Process
Step
Action
Tools Used
Findings
1. Alert Validation
Verify Azure AD alert
Azure AD Identity Protection
Confirmed password spray attack with 12 compromised accounts
2. Immediate Action
Disable compromised accounts
Azure AD, Active Directory
All 12 accounts disabled
3. Force Password Reset
Reset passwords for compromised users
Azure AD
Passwords reset; MFA enforced
4. IP Blocking
Block attacker IP
Azure AD Conditional Access, Firewall
IP 185.143.221[.]89 blocked
5. User Notification
Notify affected users
Email, Teams
All 12 users notified; training assigned
6. Threat Hunting
Check for other spray attacks
Azure AD Logs, Splunk
No other patterns found
Jira Incident Report
Ticket: SOC-2024-107 Summary: T1110 – Password Spray Attack Compromises 12 Accounts Status: RESOLVED Resolution: MALICIOUS – Accounts Secured Priority: P2 – MEDIUM Labels: T1110, brute-force, password-spray, azure-ad, identity-protection Components: Identity-Management, Access-Control
INCIDENT ANALYSIS REPORT
1. Initial Context:
Detection Source: Azure AD Identity Protection.
Alert: “Password Spray Attack Detected”.
Target: 847 Azure AD accounts.
Source IP: 185.143.221[.]89 (Bulgaria).
Time: 2024-02-21 14:15 EST.
Technique: MITRE ATT&CK T1110.003 – Brute Force: Password Spraying.
2. Technical Analysis:
Attack Details:
Type: Password spraying (one common password across many users)
Password used: “Winter2024!” (seasonal, weak)
Duration: 15 minutes
Attempts: 847
Successes: 12 (1.4% success rate – typical for password spray)
Attack Pattern:
14:00-14:12 – Failed attempts across 847 users
14:12-14:13 – Successful logins for 12 users
Attacker moved immediately to access resources
Compromised Accounts:
5 from Sales, 3 from Marketing, 2 from Finance, 2 from HR
All had weak passwords (seasonal, no complexity)
None had MFA enabled
Attacker Activity After Login:
Checked email access (OWA)
Downloaded recent emails (phishing reconnaissance)
Attempted to reset other passwords (blocked by policy)
No data exfiltration detected
Source Analysis:
IP: 185.143.221[.]89 – Bulgaria VPS
Known for credential stuffing attacks
Also used in previous campaigns
3. Investigation Findings:
Timeline:
14:00-14:12 – Spray attack
14:12-14:13 – Successful logins
14:15 – Alert triggers
14:17 – SOC investigates
14:20 – All 12 accounts disabled
14:25 – Passwords reset
14:30 – Attacker IP blocked
Indicators of Compromise (IoCs):
Network:
– Attacker IP: 185.143.221[.]89
Accounts:
– 12 compromised accounts (list attached)
Password:
– “Winter2024!” (now expired for all users)
4. Containment Actions:
Immediate Actions:
Disabled all 12 compromised accounts.
Forced password reset for each user.
Enforced MFA for all 12 users.
Blocked attacker IP at firewall and Conditional Access.
User Remediation:
All 12 users notified and required to complete security training.
Reviewed account activity for any unauthorized actions (none found).
Enterprise-wide Actions:
Scanned for other accounts using “Winter2024!” password.
Forced password changes for those users.
Sent company-wide alert about password security.
5. Root Cause Analysis:
Primary Cause: Weak, common password used across multiple accounts.
Contributing Factors:
Password policy allowed seasonal/common passwords.
MFA not enforced for all users.
No account lockout policy for multiple failures (spray attacks bypass lockout).
6. Business Impact:
Operational Impact: 12 users offline for 1 hour (password reset).
Data Exposure: Some emails accessed; no sensitive data exfiltrated.
Reputational Impact: Internal only.
7. Remediation & Prevention:
Completed Actions:
Compromised accounts secured.
Passwords reset.
MFA enforced.
Attacker blocked.
Technical Controls Enhanced:
Updated password policy to block common/seasonal passwords.
Enforced MFA for all users (Conditional Access).
Implemented smart lockout (prevents spray attacks).
Created alert for password spray patterns.
8. Conclusion:
An attacker performed a password spray attack using a common seasonal password, compromising 12 accounts. Azure AD Identity Protection detected the pattern within minutes. All accounts were secured, MFA enforced, and password policy updated.
Closure Rationale: Accounts secured; MFA enforced; password policy updated.
Analyst: [Walter White], SOC Analyst Date: 2024-02-21 15:30 EST