The phishing attacks and Trojan infections that rely on personal information stolen from Monster.com to dupe recipients have been going on for weeks, perhaps months, according to reports by security researchers.
Although Symantec only announced on Aug. 17 that it had found a hacker-controlled server containing contact information on 1.3 million Monster.com users, traces of that information can be found in messages trying to infect PCs with ransomware as early as the first week in July.
In a July 19 posting on the blog of U.K.-based security company Prevx, Jacques Erasmus, the company's director of malware research, outlined a run of spoofed Monster.com messages that hyped a download of something called Monster Job Seeker Tool. Users who took that bait, however, actually ended up infecting their Windows PCs with a piece of "ransomware" that encrypted files and demanded US$300 payment to unlock them.
"This specific email was spread on July the 6th, we know that the first infections occurred on late afternoon July the 5th," said Erasmus in text accompanying an image of the Monster-branded message.
Like other messages traced to the data-thieving Infostealer.Monstres Trojan that Symantec said looted the Monster.com resume database, the message included the real names of Monster job seekers in its salutation.
Erasmus' last comment on the blog entry was prescient: "This attack was semi targeted, using modern day personalized malware deployment methods, we will see a lot more of this in the months to come."
Last week, Symantec research Amado Hidalgo tied Infostealer.Monstres, and the personal information it ripped off from Monster's database, to attempts to infect systems with a pair of Trojans, including ransomware dubbed "Gpcoder.e." Unlike Erasmus, however, Hidalgo was able to link the purloined Monster.com contact information with the ransomware.
"While their final purpose is different, Infostealer.Monstres' and Gpcoder's modus operandi is very similar, using identical file names, creating the same system folder, injecting code into the same processes and hooking the same system functions using root-kit techniques to gain control of network functionalities and to steal sensitive information," Hidalgo said last week.
According to both Hidalgo and Monster.com, Infostealer.Monstres used legitimate usernames and passwords stolen from corporate users of the service to search the resume database and harvest the personal information later used to seed Gpcoder. Monster.com, however, has not said when the database was first pillaged. Nor would Vincent Weafer, a senior director of Symantec's security response team Symantec, hazard a guess today.
"We know we first saw Infostealer.Monstres on the August 16th, but whether that was the first version or a second version, we don't know."