Server hack and exim spamming
In this article, we will guide you in checking the issues of server hack and exim spamming. This will probably help you to find out the IP which tried the malpractices in a server to get compromised.
First, we can try to find the IP which I need to monitor
1. This netstat script will list out the number of connections made by an IP
netstat -ntu | awk ‘{print $5}’ | cut -d: -f1 | sort | uniq -c | sort -n
2. Now you got the IP then you check it out in
a. /var/log/messages
b. /var/log/secure
cat /var/log/messages | grep ip | awk ‘{print$5}’ | cut -d: -f1 | uniq -c |sort -n
grep “unauthorised attempt” /var/log/messages | awk ‘{print$5}’ |cut -d: -f1 | uniq -c | sort -n
grep “unauthorised attempt” /var/log/secure | awk ‘{print$5}’ |cut -d: -f1 | uniq -c | sort -n
Note :-Check Server hack and exim spamming, In {print$5} value may change it can become 7, 8, 11, 12 etc …. eg:- {print$7}
EXIM COMMANDS
To view the mail queue:
exim -bp
Number of mail in the queue:
exim -bpc
To open a mail:
exim -Mvh
The number of emails in the queue:
exim -Mvh
How many Frozen mails on the queue:
/usr/sbin/exim -bpr | grep frozen | wc
Deleting Frozen Messages:
/usr/sbin/exim -bpr | grep frozen | awk {‘print $3′} | xargs exim -Mrm
To know the number of frozen mails in the mail queue, you can use the following command
exim -bpr | grep frozen | wc -l
In order to remove all frozen emails from the Exim mail queue, use the following command
exim -bpr | grep frozen | awk {‘print $3′} | xargs exim -Mrmrm
You can also use the command given below to delete all frozen mails
exiqgrep -z -i | xargs exim -Mrm
To flush the exim queue
exim -qff
Base64 injection scripts
We can use this script to find out the PHP script
grep “authentication failure” /var/log/secure | awk ‘{ print $3}’ | cut -b7- | sort | uniq -c
find /var/www/vhosts/ -name “*.php” | xargs -I{} sed -i ‘/<?php eval(gzinflate(base64_decode(/d’ {};
How to Find the spammer spamming from home directory
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The spammer may use his home directory for spamming we can use a script to locate the top scripts on your server that send out the email. Then you can search the Exim mail log for those scripts to determine if it looks like spam, and even check your Apache access logs in order to find how a spammer might be using your scripts to send out spam.
grep cwd /var/log/exim_mainlog | grep -v /var/spool | awk -F”cwd=” ‘{print $2}’ | awk ‘{print $1}’ | sort | uniq -c | sortrt -n
To find suspicious IP activities
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This will list the entries for the IP Address in question ( replace ip.add.re.ss with the suspicious IP address )
find /var/log/ -exec grep “ip.add.re.ss” ‘{}’ ; -print
This script will provide you top 10 IP addresses that hit your apache access log
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cat /var/log/httpd/access_log |awk ‘{print $1}’|cut -d? -f1|sort -n|uniq -c|sort -n|tail -10
This script will list the ten most accessed files on your site
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This script will Sort files and display the number of times that file was accessed
cat /var/log/httpd/access_log |awk ‘{print $7}’|cut -d? -f1|sort -n|uniq -c|sort -n| tail -10
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