While many Americans were busy getting ready to celebrate the July 4 holiday, spammers were busy trying to trick unsuspecting victims into clicking on malicious Independence Day themed malware messages.
It's a familiar pattern—hackers attempting to trick unsuspecting victims into clicking on a link related to a holiday or major event. On July 3, email intelligence and security vendor Cofense reported that its systems tracked phishing attacks using the Geodo botnet malware, sending patriotic emails timed to coincide with the holiday.
"The timing—a day prior to the holiday—comes as no surprise here," Brendan Griffin, technical product manager at Cofense, told eWEEK. "The emails were delivered on the final business day prior to the holiday, at a time when people are likely in their offices or at least checking and responding to emails, and are more likely to be rushing to wrap things up prior to the holiday."
Cofense, which was formerly known as PhishMe but rebranded itself on Feb. 26, reported that the phishing emails sent by the Geodo botnet had a patriotic message that encouraged recipients to click on a link to see an Independence Day-themed greeting card. The link downloads a Word document with a macro script that in turn downloads and installs the Geodo malware. The malware then attempts to steal sensitive information from a victim's system.
Griffin said the Geodo sample seen by Cofense did not take advantage of any zero-day vulnerabilities. "Instead, it relied on a potential victim to be susceptible to the phishing lure and to interact with and thereby enable the macro scripting," he said. "Lately, the delivery of malware via malicious macros has resurged in popularity amongst threat actors because it allows adversaries to abuse a key feature of a platform that is integral to several business operations."
It's not known how many victims the Geodo July 4 phishing campaign claimed. Part of the reason it's hard to measure, according to Griffin, is because Geodo will carry out different missions as time passes. That said, he noted that Cofense is confident that the number of emails is large, since one of Geodo's key characteristics is to use every new infection to generate new phishing emails to further spread its reach, which can lead to massive numbers of emails in a relatively short time. He added that Geodo is consistently among the malware that Cofense observes in phishing campaigns.
"It is also important to bear in mind that the rest of the world continued to be targets of common phishing attacks on the holiday itself," Griffin said. "Yesterday [July 4], we saw the same common campaigns we always see globally, none of which included any reference of July 4th as global business carried on as usual."
Holiday-themed targeting is opportunistic, and the volume really varies year by year, he said. Threat actors attempt to use different types of narratives to understand what works—and they may intentionally vary this in order to keep users off-guard.
"This specific Geodo campaign was very specific in timing and theme—and it came with a very provocative narrative, intended to connect to a user's sense of patriotism and emotional connection through an alleged e-card," Griffin said.
Phishing is not a new problem, though it is an attack vector that remains successful for several reasons. Griffin said that threat actors are constantly evolving and innovating to find ways to get past automated network defenses and reach users’ inboxes.
"It is critical to educate users to identify and report suspicious emails," Griffin said. "This way, users do not only become the last line of a successful defense, they also enable enterprises to know what campaigns are successfully getting onto their network and rapidly respond to them."
Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.