Frequent access requests from user agents that are known to be associated with malicious tools or bots.

This IP belongs to Dow Chemical.

The IP attempted to perform a SIP Invite Flood on the SIP server.

This IP belongs to Comcast.

It attempted to use the FTP server to distribute password cracking tools.

The IP made multiple unsuccessful login attempts to the IMAP server in a short period of time.

This IP belongs to PepsiCo.

POST /login.jsp?user=admin&pass=admin: This could be an attempt to log in as an admin.

Unusual patterns of behavior, such as login attempts at regular intervals or sequential patterns in the attempted passwords.

Repeated requests for the same file or page, indicating an attempt to crack a password or exploit a vulnerability.

The IP attempted to bypass IP blacklisting by rapidly changing its IP address.

This IP belongs to MetLife.

Remote File Inclusion (RFI): You might see HTTP requests with "=http" or "=ftp" which can signal an attempt for remote file inclusion.

The IP attempted to perform ARP Spoofing attacks on the Apache server.

Uncommon Referer Header: HTTP logs record requests from an uncommon or suspicious 'Referer' header.

It attempted to perform a phishing attack using the POP3 server.

The IP made multiple requests to the server's robots.txt file.

It attempted to login to the SSH server with an invalid password.

It attempted to use the FTP server to store illegal content.

It made multiple requests with identical cookies.

Attempts to access the server using known malicious IP addresses or domains.

Unidentified password attempts and login activity were noticed from the specific IP address.

The IP attempted to use the FTP server to distribute keylogging software.

The IP attempted to bypass IP blacklisting by rapidly changing its IP address.

The IP attempted to login to the SASL server with an invalid username.