Windows 2003/XP/2000/NT/ME/98/95

Sinowal.WVJ is a Trojan, which although seemingly inoffensive, can actually carry out attacks and intrusions.

It captures certain information entered or saved by the user, with the corresponding threat to privacy: passwords saved by certain Windows services.

It reduces the security level of the computer: it changes the security settings of Internet Explorer, decreasing its security level; it awaits remote-control orders received through HTTP; it changes system permissions, decreasing the security level.

It uses stealth techniques to avoid being detected by the user:

• It uses techniques included in its code to hide itself while it is active.
• It injects itself in running processes.
• It deletes the original file from which it was run once it is installed on the computer.

It uses several methods in order to avoid detection by antivirus companies:

• It terminates its own execution if it detects that it is being executed in a virtual machine environment, such as VMWare or VirtualPC.
• It prevents scanning tools from running, such as Windows Registry Editor, FileMonitor, etc.

Sinowal.WVJ uses the following propagation or distribution methods:

• Exploiting vulnerabilities with the intervention of the user: exploiting vulnerabilities in file formats or applications. To exploit them successfully it needs the intervention of the user: opening files, viewing malicious web pages, reading emails, etc.
• Via Internet, exploiting remote vulnerabilities: attacking random IP addresses, in which it tries to insert a copy of itself by exploiting one or more vulnerabilities.