Java 'Icefog' Malware Variant Infects US Businesses

9 Notorious Hackers Of 2013

Beware Java-based malware that's been used to exploit at least three US-based organizations.

That warning of a new advanced persistent threat (APT) attack campaign came via Kaspersky Lab, which said that it's traced a malicious Java archive (a.k.a. JAR) file to eight infected systems inside three US-based organizations, which it declined to name. "Based on the IP address, one of the victims was identified as a very large American independent oil and gas corporation, with operations in many other countries," Kaspersky Lab researchers Costin Raiu, Vitaly Kamluk, and Igor Soumenkov said in a joint blog post Tuesday. "As of today, all victims have been notified about the infections. Two of the victims have removed it already."

The attacks have been tied to the Icefog APT attack campaign, which historically has used Windows Preinstallation Environment files to infect targets.

What's unusual about the latest attacks is that the "Javafog" malware used by attackers was, as the name implies, written in Java. Furthermore, it includes only basic functionality, such as the ability to upload files to a designated server, as well as change the command-and-control (C&C) server to which it reports. "The backdoor doesn't do much else," according to Kaspersky Lab. "It allows the attackers to control the infected system and download files from it. Simple, yet very effective."

[Will US tech businesses pay a steep price for government surveillance? See NSA Fallout: Why Foreign Firms Won’t Buy American Tech.]

Why bother with a backdoor written in Java? "Malware written in Java code, like the Javafog Trojan, is extremely difficult to detect and therefore can remain stealthy for longer periods of time," says Dana Tamir in an email. Tamir is director of enterprise security at IBM-owned Trusteer, which sells a number of products that employ Java. As of Tuesday, the malware was being spotted by only three out of 47 antivirus engines on VirusTotal.

Blocking Java-based malware isn't difficult, provided businesses can eradicate older versions of the Java browser plug-in. "To prevent Java exploits and malware-based infiltrations, it is important to restrict execution only to known trusted Java files," says Tamir. "Organizations should at least restrict execution to files that have been signed by trusted vendors, or downloaded from trusted domains."

Patching known vulnerabilities is also a must. Indeed, at least one of the Javafog infections resulted from attackers exploiting known vulnerabilities in systems inside targeted organizations. "In one particular case, we observed the attack commencing by exploiting a Microsoft Office vulnerability, followed by the attackers attempting to deploy and run Javafog, with a different C&C," the Kaspersky Lab researchers said. "We can assume that based on their experience, the attackers found the Java backdoor to be more stealthy and harder to notice, making it more attractive for long-term operations."

If so, that would represent a changeup in the tactics being employed by the group behind the normal "smash and grab" Icefog attack campaign, which Kaspersky Lab discovered in September 2013. Kaspersky Lab said it has targeted "government institutions, military contractors, maritime, and ship-building groups." Previously the majority of targets were located in Japan and South Korea.

Whereas most APT campaigns employ "low and slow" attacks to create an undetected, long-term presence inside a targeted network, Icefog attacks differ. Notably, attackers appeared to be grabbing what they wanted and then ceasing their attack. Kaspersky Lab said that modus operandi suggested that the attackers were a "cybermercenary group" intent on stealing only designated bits of information.

If so, who commissioned the Icefog campaign? According to threat intelligence firm CrowdStrike, which refers to the attack campaign as "Dagger Panda," it's being run from China, which suggests that the hackers for hire have the backing of the Chinese government.

Last year, Adam Meyers, CrowdStrike's head of intelligence, said that China's five-year plan to modernize its infrastructure, including adding more deep-sea military capabilities, appeared to tie to a series of cyberattacks against US targets. Those attacks resulted in the theft of information pertaining to satellite technology, torpedoes, naval antennas, radar, and a naval ballistic-missile defense system, amongst other technology, all of which would be useful for improving deep-sea operations.

Icefog-related attacks date to at least 2011. That's when related malware was first discovered, which exfiltrated data from infected systems via email, and which was used to successfully infect systems inside both the Japanese House of Representatives and House of Councillors. Subsequent versions of Icefog added C&C capabilities and script-based proxy servers. A Mac OS X version dubbed "Macfog" also appeared to have been used to successfully infect several hundred Mac systems.

Kaspersky Lab said that although it only recently verified Javafog's existence, the underlying JAR file dates to Nov. 30, 2012, which suggests that it was in use for some time before being discovered, and that it may tie to long-term operations against US targets. "This brings another dimension to the Icefog gang's operations, which appear to be more diverse than initially thought," the Kaspersky Lab researchers said.

Mathew Schwartz is a freelance writer, editor, and photographer, as well the InformationWeek information security reporter.

Next-gen intrusion-prevention systems have fuller visibility into applications and data. But do newer firewalls make IPS redundant? Also in the The IPS Makeover issue of Dark Reading Tech Digest: Find out what our 2013 Strategic Security Survey respondents have to say about IPS and firewalls. (Free registration required.)