Splunk SSH Alert

Monitoring SSH login activity is crucial for security. This guide walks you through setting up a Splunk alert that detects successful SSH logins and sends formatted Slack notifications with essential details.

🎯 Splunk Query to Detect Successful SSH Logins Link to heading

Use the following Splunk search query to detect successful SSH logins from /var/log/auth.log.

index=* "Accepted password for" OR "Accepted publickey for" source="/var/log/auth.log" 
| rex field=_raw "Accepted (?<auth_method>\w+) for (?<user>\w+) from (?<ip>[\d\.]+) port (?<port>\d+)"   
| eval formatted_time=strftime(_time, "%Y-%m-%d %H:%M:%S") 
| table formatted_time host user ip auth_method port  
| eval slack_message="🚀 *Successful SSH Login Alert*\n👤 *User:* `".user."`\n🖥️ *DEST Host:* `".host."`\n🌐 *SRC IP:* `".ip."`\n🔑 *Method:* `".auth_method."`\n⏰ *Time:* `".formatted_time."`"

📝 Explanation: Link to heading

Filters logs to find SSH logins (password/public key authentication).
Extracts key details using rex (regex extraction):
- 👤 user: Username
- 🌐 ip: Source IP
- 🔑 auth_method: Authentication method
- 🖥️ host: Destination machine
Formats the timestamp into YYYY-MM-DD HH:MM:SS using strftime().
Constructs the Slack message with emojis for better readability.

🔔 Configuring a Splunk Alert to Send Slack Notifications Link to heading

🛠️ Step 1: Create a New Alert Link to heading

Go to Splunk UI → Settings → Searches, Reports, and Alerts.
Click Create New Alert.
Set the Trigger Condition:
- Trigger if Number of Results > 0.
- Set an appropriate schedule (e.g., every 5 minutes).

🔗 Step 2: Configure the Slack Alert Action Link to heading

Enable Slack Alert action in Splunk.
Set up a Slack Webhook URL (replace with your actual webhook):

https://hooks.slack.com/services/YOUR/SLACK/WEBHOOK

Use the following Slack message format:

{
  "text": "🚀 *Successful SSH Login Alert*\n👤 *User:* $result.user$\n🖥️ *DEST Host:* $result.host$\n🌐 *SRC IP:* $result.ip$\n🔑 *Method:* $result.auth_method$\n⏰ *Time:* $result.formatted_time$"
}

Save & Enable the Alert! 🎉

✅ Example Slack Notification Output Link to heading

When triggered, Slack will receive a message like this:

🚀 Successful SSH Login Alert  
👤 User: james  
🖥️ DEST Host: 10.10.10.10  
🌐 SRC IP: 10.10.10.100  
🔑 Method: publickey  
⏰ Time: 2025-03-16 15:14:59

🎯 Final Thoughts Link to heading

By setting up this Splunk alert, you ensure real-time monitoring of SSH logins while improving security visibility. You can modify the query to:

✅ Include more details (e.g., failed logins, geolocation lookup).
✅ Trigger different actions (e.g., email alerts, automated responses).

🔹 Now your Slack is your security dashboard! 🚀🔐

🚀 Splunk SSH Login Alert Link to heading