Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
304 detections
Filters
Last updated
All Time
Detection languages
161
41
35
31
16
Contributors
117
32
24
22
21
Categories
195
89
66
58
57
Platforms
112
82
58
58
26
Products / Services
67
46
45
44
42
MITRE Techniques
18,123
15,639
12,580
8,394
6,215
CVEs
5
2
2
2
1
IDS Classtypes
35
3
2
1
1
IDS Protocols
37
3
1
1
This rule detects an unusually high volume of logon events (both successful and failed) or a large number of unique users attempting to log on within a 5-minute window. This behavior is indicative of potential brute-force attacks or credential stuffing attempts against Windows systems.
Detects multiple failed Kerberos pre-authentication attempts (EventID 4771 with status codes 0x18 or 0x1f) from a single IP address against a target user within a short timeframe (20 attempts in 5 minutes). This pattern is indicative of a brute-force attack against Kerberos accounts.
This rule detects potential brute force attacks against Active Directory accounts by identifying multiple failed login attempts (EventID 4625) from the same IP address to the same account within a short time frame (10 failed attempts within 10 minutes).
This rule detects potential brute force attacks against Azure AD accounts by identifying users with 10 or more failed sign-in attempts due to invalid credentials within a 5-minute window. It summarizes the failure count and associated IP addresses for each user.
This rule detects potential brute force or enumeration attempts against an IIS web server by identifying a high volume of access denied (HTTP 401 or 403) responses from a single IP address within a one-hour window. A count of 20 or more such responses from the same IP is considered suspicious.
Detects an unusually high volume (100 or more within an hour) of API calls (POST, DELETE, PUT methods to URIs containing 'api') originating from a single IP address. This activity could indicate various malicious behaviors such as brute-force attacks, credential stuffing, web application attacks, or a denial-of-service attempt against the API endpoint.
This rule detects a high volume of POST requests to login, authentication, or password-related URI stems within a 5-minute window from unique IP addresses. This behavior is indicative of brute-force attacks or credential stuffing attempts against web applications.
This rule detects potential brute force or enumeration attempts against an IIS web server by identifying a high volume of access denied (HTTP 401 or 403) responses from a single IP address within a one-hour window. A count of 20 or more such responses from the same IP is considered suspicious.
This rule detects an FTP brute force attempt by monitoring TCP connections to port 21 (FTP) on the home network. It triggers an alert if 20 or more TCP SYN packets (indicating new connection attempts) are observed from the same source IP address within a 60-second window. This behavior is indicative of an attacker repeatedly trying to guess FTP credentials.
This rule detects a potential SSH password brute force attack. It triggers an alert if there are 30 or more TCP connections to port 22 (SSH) on the home network from a single source IP address within a 60-second window. The 'flow:to_server' and 'flags:S' indicate that it's looking for new connection attempts (SYN packets) directed towards the server.
This rule detects a pattern indicative of password spraying or brute force attacks against user accounts. It identifies instances where a single user principal name (UPN) and IP address combination has at least 5 failed sign-in attempts and at least 1 successful sign-in attempt within a 30-minute window. This combination of failed and successful logins from the same source for the same user suggests an attacker successfully guessed a password after multiple attempts, or a password spraying attack where one of the sprayed passwords was correct.
SSH Brute Force Attempt Detected
Suricata
Detects repeated failed SSH authentication attempts which may indicate brute force activity against SSH services. The rule specifically looks for 8 SSH connection attempts to port 22 within a 60-second window from the same source IP.
This rule detects a successful Remote Desktop Protocol (RDP) login that is immediately preceded by 20 or more failed RDP authentication attempts from the same source IP to the same destination IP within a 15-minute window. This pattern is indicative of a brute force attack that has successfully compromised credentials.
This rule detects a high volume (50 or more) of failed authenticated SMTP login attempts to Office 365 Exchange Online from a single IP address within a 24-hour period. The failures are specifically for error codes 50126 (invalid username or password) or 50053 (account locked). This pattern is indicative of a brute-force or password-guessing attack against Exchange Online accounts.
This rule detects an IP address attempting to log in unsuccessfully to more than 20 distinct user accounts. This behavior is indicative of a brute-force attack or password spraying attempt against multiple accounts from a single source.
This rule detects an IP address attempting to log in unsuccessfully to more than 20 distinct user accounts. This behavior is indicative of a brute-force attack or password spraying attempt against multiple accounts from a single source.
Detects 5 or more failed logins to a firewall management interface, followed immediately by a successful login for the same user and from the same IP.
This rule detects external brute-force attempts against firewall authentication mechanisms. It triggers when 15 or more failed login attempts from a single external IP address occur within a 15-minute window. The rule specifically filters for 'USER_LOGIN' events with a 'BLOCK' or 'FAIL' security result and excludes internal RFC1918 IP addresses to focus on external threats.
Detects inbound network connections and Azure AD sign-in attempts originating from the 21-IP RDP scanning fleet attributed to AS213438 (ColocaTel Inc., Seychelles), as reported by GreyNoise on April 10, 2026. The fleet generated 67.4% of global RDP Crawler activity on April 7, 2026 across four /24 blocks geolocated to the Netherlands. The same ASN demonstrated a burst-and-crash pattern in both March and April 2026, suggesting further rotations are likely.
This rule detects multiple failed authentication attempts for a single user from a specific source IP and host. This behavior can indicate a brute-force attack or password guessing attempt against user accounts.
Detects multiple failed FortiGate VPN login attempts using known default usernames, consistent with The Gentlemen brute force campaigns. They maintain ~969 validated brute-forced FortiGate VPN credentials and test anti-honeypot probe passwords with Russian garbage strings.
Page 10 of 15