The iframe assaults from hackers are done by:
Client side PC infected with the virus.
The virus gets FTP username or password from the FTP clients.
Utilizing the username or password, the virus downloads the file documents, include iframe code and re-upload it.
The iframe code focuses to a similar virus. Along these lines, anybody getting to this site gets infected with a similar virus, and it utilizes the FTP username or password spread once more.
Temporary solution
The bandaid fix for such an issue is to change the FTP username or password.
Permanent solution
1. Change the password of the infected clients.
2. Before updating the new password in the FTP clients, do a full framework Virus examine with a dependable infection scanner updated with the most recent infection definition files.
3. Try not to spare (recall) the FTP username/password on FTP clients.