Win32/Sinowal is a family of password-stealing and backdoor Trojans. The Trojan may try to find a cryptographic certificate on the infected computer and install a certificate on the computer to mislead users in Secure Sockets Layer (SSL) Web transactions. The Trojan may also capture user data such as banking credentials from various user accounts and send the data to Web sites specified by the attacker. Some Win32/Sinowal components may also open a backdoor on a TCP port. Win32/Sinowal may try to perform certain operations from the context of a trusted process such as explorer.exe in order to bypass local software-based firewalls.
Malicious Software Encyclopedia: Win32/Sinowal