Backdoor:PHP/C99shell.G(Microsoft), Backdoor.PHP.C99Shell.AQ(Fsecure), Malware_fam.B(Fortinet), PHP/Rst.AK(ESET)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
This malware is part of an attempted PHP backdoor attack via spam that took place on March 2014. Users affected by this malware would be shown a user interface of the malware's control panel, which shows its backdoor capabilities.
To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.
This malware arrives via the following means:
This malicious PHP script may be uploaded and installed on a web server by a remote malicious user via FTP after gaining access to the said server.
Once this PHP script is installed, the user may then launch a backdoor on the affected system.
Opening the page, the malicious user is shown the following GUI:
It has the following backdoor capabilities:
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Scan your computer with your Trend Micro product to clean files detected as PHP_C99SHEL.SMC. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.