How to find the source of spam emails on my server?

Can you tell me the effective way to find which script or email accounts on my server is sending spam emails?
My server IP address is getting uceprotectl3 blacklist but I don't know which email caused that.

Many thanks!

Just ignore uceprotect shit, they do that to request money from ppls to delist it they or better to say he because is one man are scammer/s, are you with OVH by any case?
More about those morons:

and many more, just type on google uceprotect scam.

Make sure you have done everything I am mentioning below:

1. Check Mail Logs
2. Examine SMTP Logs
3. Inspect the Outgoing Email Queue
4. Enable Detailed Logging
5. Implement Email Authentication
6. Check User Accounts
7. Review Website Scripts
8. Implement Rate Limiting
9. Use Spam Traps
10. Scan for Malware
11. Monitor Network Traffic

If still a problem, contact your services providers to Seek Professional Assistance. Thank You...

UCEPROTECT is BS. Check to see if your IP address is listed in any reputable RBL's using MxToolbox:

UCEPROTECT (also known as UCEPROTECT Network) is a controversial blacklist service that aims to identify and list IP addresses that are associated with spamming activities. It was created by a German company and gained some popularity among email service providers and administrators as a means to block spam from specific IP addresses.

Plenty of negative stories about them, OP. I would follow the advice of other posters, and ignore them.

Well, or you can just close port 25

Kidding.

Yes, it was correctly written here above that it is necessary to log everything and look at the logs to see if such a problem really exists.
Start simple - how many emails are leaving you and further coarsen searches, see which account sends more emails, and then you can log the emails themselves, if you are the owner and administrator of the server and suffer from violations - you have the right to figure it out. IMHO.

Ato sometimes even cool spambases without understanding enter into violators with entire subnets, when only one IP address is spamming.

Please take a look at what I've mentioned below.
• Check Mail Logs
• Analyze Email Headers
• Enable Email Authentication (SPF, DKIM, DMARC)
• Review Server Scripts and Applications
• Monitoring and Tracking
• Examine Server for Malware
• Check for Open Relays
• Review Mail Queue
• Implement Rate Limits
• Consult with Your Hosting Provider

To identify the source of spam emails on your server, start by checking the mail logs for any unusual activity or high email volumes. Analyze email headers of received spam to trace the source IP address. Implement email authentication (SPF, DKIM, DMARC) to prevent email spoofing. Conduct malware scans on the server to detect any malicious scripts or applications. Secure all email accounts with strong passwords and review website scripts for potential vulnerabilities.

Here's a example of how to apply the steps mentioned to identify the source of spam emails on your server:

Step 1: Checking Mail Logs Login to your server using SSH or any control panel provided by your hosting provider. Access the mail logs, typically located in the "/var/log/maillog" or "/var/log/exim_mainlog" file. Look for any suspicious activity or a sudden increase in outgoing email volume.

Example command to check mail logs:

Step 2: Analyzing Email Headers If you receive a spam email complaint from a recipient, ask them to forward the email with headers intact. Examine the email headers to identify the source IP address, sender, and any suspicious elements. The headers will show you the path the email took to reach the recipient.

Example email header (excerpt):

Step 3: Implementing Email Authentication Access your server's control panel or email configuration settings to enable SPF, DKIM, and DMARC. These settings will vary based on your hosting provider or mail server software. Typically, you'll find options to add TXT records for SPF and DKIM, and set DMARC policies.

Example SPF DNS record:

Step 4: Conducting Malware Scans Use antivirus or malware scanning tools to perform a thorough scan of your server's files and directories. Many hosting control panels offer built-in security tools for this purpose. Additionally, you can use command-line tools like ClamAV.

Example command to scan with ClamAV:

Step 5: Securing Email Accounts and Reviewing Scripts Ensure all email accounts have strong, unique passwords to prevent unauthorized access. For website scripts, review them for potential vulnerabilities and keep all software, including CMS and plugins, updated to the latest versions.

By following these real examples and applying the mentioned steps, you can effectively identify the source of spam emails on your server and take appropriate measures to mitigate the issue and enhance your server's security.