November 28th, 2009 
Aneesh
This year, there has been a large increase in the number of legitimate websites infected by a so-called “iframe” threat – a type of malicious script.
Several prominent websites have come under attack from hackers who have modified the underlying code so that malware can be distributed to unsuspecting users who visit the site. When a user visits an infected site, an invisible connection is established to a remote server, which can then attempt to install malware on the user’s computer. The intention could be to generate spam, or possibly something more sinister, such as stealing personal information e.g. bank account or credit card details. The above texts are taken from Avast news letter]
How does Iframe attack happens ?
Iframes are inserted to web sites files through FTP. Normally , people (developers, webmasters etc) used to save the ftp password in their FTP client programs (Cute FTP, filezilla etc). In such case, if that system is infected with virus or any malware the saved ftp password will be taken and emailed to hackers (who created the virus or malware to get the ftp details of web sites). Once hackers get this ftp password, they have automated system to insert the Iframe to web site files thorugh their FTP program. Once the iframes are inserted to the website, when users broswse the infected website their system also get infected with malware or virus. If users are using a good antivirus program they may get a warning that the server is infected.
What can i do if my system is infected ?
I did not find any anti virus program that will detect the virus or malware. I think it is best idea to Format the system and reinstall everything than taking RISK. Also Enable Firewall in the system after installing the OS
What all security methods can be taken in order to prevent this kind of iframe attack ?
Since the Iframe attack happens thorugh FTP password our first attention should go to securing FTP server. Instead of using normaly FTP, use SFTP and this can help us upt to an extend. Also, the best idea is to allow FTP access from allowed IPs only. This can be done using either software or hardware firewalls. Since , hardware firewall is expensive we can think of software firewalls. For windows IIS ftp service, we can deny all ips except allowed IPs. For linux this can be done using Iptables (http://www.hellosystemadmin.com/restrict-ftp-access-using-iptables/). The above tasks can be done by an administrator only and this will not be so a fast method when FTP usrs have dynamic Ip address. So we need to think about creating some scripts (php , VB, shell ) which can be used by all users. For example in a linux server we can create some PHP script which will use Iptables command to add his ip to the firewall. I suggest a simple algorithm to do this task
Create a mysql database with two tables ‘users’ and ‘rules’ . The table ‘users’ includes the customer Id and password. And the second table should include CustomerID, IPAddress and Status (You can add any other fields according to your convenience). Now we needto create a php script which will call iptables command to add the firewall rule. Follwoing is sampel rule
iptables -I INPUT -s XXX.XXX.XXX.XXX -d 0.0.0.0-p tcp -m tcp €“dport 21 -j ACCEPT
In the above command, we can pass the IP address and Status as php variables
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Wonderful.
Thanks for the information. What can we do if my system is infected
Thanks
Geoffrey
You need to immeidately change your FTP password. Now download all files and clean all files and make sure that it is free from bad code.
While I believe this is truly good info I am not sure if it is for me
There has not been a virus attach lately. Is antivirus firewall severity overrated?
There has not been a malware damage lately. Is antivirus firewall threat overrated?
You need to manually clean all files by editing each files and removing the bad codes
You made some Good points there. I did a search on the topic and found most people will agree.
Title…
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thanks for this usefull informations..
Hey I just received a popup from my firewall when I opened your page do you happen to know why this occured? Could it be from your ads or something? Thanks, really strange i hope it was harmless?
Dear Abdul,
There’s nothing bad in this site. we have added Google ads in the site and these ads are called from Google Site. If you do not allow that , the ad will not be displayed in the site. If you need to know anything more please feel to contact us.
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After searching for this information, I will have to say most people agree with you on this topic.
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When I originally commented I clicked the “Notify me when new comments are added” checkbox and now each time a comment is added I get four emails with the same comment. Is there any way you can remove me from that service?Thanks
Dear Jimmy,
I will take care of this problem if it still exists.
Thank You,
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I admit, I have not been on this blog in a long time… all the same it was another happy to see It is such serious topic and avoided by so many, even professionals. I thank you to assist making people more awake of possible problems.
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Hello just thought i would tell you something.. This is twice now i’ve landed on your blog in the last 3 days searching for completely unrelated things. Spooky or what?
Hi,
Please tell me how did you land on this site. What were you searching ?. I added only technical articles here.
Thank You,
Aneesh Joseph
Author – Hellosystemadmin.com
I really like your post. Always been very informational. I hope you’ll keep up the good work and maintain the standard. Best of luck.