Attackers have broadened both the capabilities and targets of malware first spotted primarily targeting financial institutions in Japan.
According to PhishLabs, the reach of the Vawtrak malware has been expanded to include social networks, online retailers, analytics firms and game portals across several different countries including the United States, Canada and the U.K. In addition, newer configurations of the Vawtrak botnet have advanced web injects that enable the theft of additional personal information for exploiting the victim’s account.
Just how big the botnet is isn’t easy to say.
“In estimating the magnitude and scope of the Vawtrak botnet threat accurately, PhishLabs takes into account first-hand sources such as the number of Vawtrak botnets and partitions, as well as logs from the spam botnets…and exploit kits (recently, Nuclear Pack) used to distribute Vawtrak,” Don Jackson, director of threat intelligence at PhishLabs, explained in an email.
“The most authoritative source is the Vawtrak admin panels used to manage the botnets themselves,” he continued. “Of the infection numbers from admin panels available to PhishLabs R.A.I.D. [Research, Analysis, and Intelligence Division], the total number Vawtrak infections increased from approximately 65,000 in 2013, to a number that fluctuates between 100,000 [and] 300,000 currently.”
What researchers do know is that while one arm of the operation recently scaled back attacks on targets in Japan, China and other countries, the core Russian crew ramped up large-scale attacks on targets in the U.S., Jackson noted in a blog post.
“In July, samples from the Russian crew’s new operation were configured to use advanced webinjects attacks against as many as 64 targeted organizations’ web sites, including financials, social networks, online retailers (including StubHub), analytics firms, and game portals,” he blogged.
“Since the StubHub arrests, the Vawtrak crew has modified configurations to evade authorities and increase the chance of success,” he wrote. “The newest configuration being pushed to bots on August 28, 2014, represents major changes made over the last 30 days. Vawtrak’s advanced webinject capabilities are similar to other state-of-the-art banking Trojans, allowing it to modify data in web traffic, even if it has been secured with encryption. Vawtrak uses this capability to steal login credentials, automate fraudulent transactions inside online banking sessions, and inject addition form fields into legitimate web pages to gather additional information, such as social security numbers or PINs, for use in banking fraud and identity theft.”
Recently, Vawtrak has been utilized in a spam template injected into the Cutwail botnet. The attack is aimed at exposing victims to an exploit kit that steals the user’s banking credentials. The attacker then uses a virtual network computing server to take control of the compromised machine and log into the bank account.
The fact that the malware is coming in through Cutwail shows whoever is behind the attacks is “spending serious real-world money to infect more banking customers,” Jackson noted.
“The explicit StubHub attack instructions are still in the latest configuration,” he wrote. “Overall, the Vawtrak operation seems unaffected by the arrests and continues at the same frenetic pace since its June 2014 vre-emergence. In fact, with the void left by the demise of other botnets like Spy Eye, Shylock, and Gameover Zeus, it’s possible that the Vawtrak crew is poised to either scale up operations, or begin offering Vawtrak as crimeware-as-a-service (CaaS).”