Malware Developers Port Linux DDoS Trojan to Windows

Researchers at Russia-based security company Doctor Web have noticed that a piece of malware designed to run on Linux computers has been ported by its creators to Windows.

In May, Doctor Web uncovered several Linux Trojan variants that appeared to have been created by the same individual or group located in China. The threats, part of malware families dubbed Linux.DDoS, Linux.Mrblack and Linux.DnsAmp, are capable of abusing infected Linux machines for various types of distributed denial-of-service (DDoS) attacks.

The security firm reported last week that Linux.DnsAmp was ported to Windows. Trojan.DnsAmp.1, the Windows version of Linux.DnsAmp, is installed on affected systems as a service called “Windows Test My Test Server 1.0,” with the main executable file being dropped into the %System32% folder as “vmware-vmx.exe.” The threat is designed to activate only if the system date is set after 02.21.2013, otherwise it remains idle.

Then, the malware collects information on the infected system and sends it back to its command and control (C&C) servers. Once this is done, the attackers can command the Trojan to start or stop a DDoS attack. DnsAmp.1 is capable of SYN flood, UDP flood, ping flood and HTTP Get flood attacks. The Linux version can be used for DNS amplification, instead of HTTP Get flood attacks, the experts said.

In addition to launching DDoS attacks, the Trojan can also be utilized to download and execute other malicious software on infected devices.

Doctor Web has been monitoring infections and found that between June 5 and August 13, most of the affected machines were located in China (28,093 infections representing 79.1% of the total). According to the company, 9.4% of infections were traced to the United States. 

 Last month, Kaspersky described a similar DDoS Trojan for Linux whose most interesting feature was the ability to conduct DNS amplification attacks. Unlike other Linux Trojans, this one had a sophisticated modular structure.