Email scams in which cybercriminals attempt to extort money from victims by threatening to reveal something embarrassing about them are on the rise.
According to Symantec, between January and the end of May this year, it blocked some 289 million scam emails, many of them involving so-called "sextortion" attempts. Of these, about 30% were sent during a 17-day period around Valentine's Day. The blocked emails were written in English and a dozen other languages, including Chinese, German, Italian, and Japanese.
Sextortion is a type of email scam where cybercriminals attemps to extort money from individuals by claiming to have a recording of them engaged intimate acts. Often the scam email informs victims that their webcams were hacked and used to make recordings of them visiting porn sites.
Attackers demand that victims send a specified amount of money in Bitcoin or other cryptocurrency — or risk having the alleged recordings sent to every contact in their address books. The emails convey a sense of urgency by demanding the victims pay the extortion amount with 24 or 48 hours.
The scam emails often include passwords and phone numbers recipients may have used or are currently using to give the impression the attackers have access to a lot of their personal information. The goal is make users fear their computers might have actually been hacked and used to observe potentially compromising actions.
In reality, the criminals likely obtained the data from one of the many large password dumps that have happened in recent years, Symantec said. In some cases, attackers have purported to be members of law enforcement who have discovered child pornography on victims' computers.
Not all email scams that Symantec blocked in the first five months of this year were sextortion-themed. Several were bomb-scare emails where the sender claimed to have planted a bomb in a building that would be triggered unless the requested amount is paid in full.
The scam emails typically followed the same pattern with relatively minor variations in the messages. Some, for instance, included PDF attachments, others had links pointing to malicious sites, while some contained obfuscated text and other characters designed to evade spam filters. Users opening the attachments or clicking on the URLs to see the purported recording of their activities often ended up downloading malware on their systems.
For cybercriminals, mounting such scams is easy because all it involves is sending a spam email, says Kevin Haley, director of security response at Symantec. "You can take a new idea, throw it against the wall, and see if it works. If not, move on to the next idea," he says.
Blackmailing people over their alleged sexual activity is not new. But the abundant email lists and credential data available on the Dark Web these days has made it relatively easy for attackers to launch convincing-looking scam campaigns, Haley notes. Often victims are tricked into believing attackers might have gathered personally compromising information.
"For the amount of effort and skill that is required to carry out these scams, it's a solid return on investment [for attackers]," Haley says. Symantec estimates that the 5,000 most-seen Bitcoin addresses received a total of about $106,240 in May. "If we take that number as the average amount to make in a 30-day period for these kinds of scams, that's just over $1.2 million in a year," Haley says.
For the most part, sextortion scams are consumer-focused. But reports about attackers using spear-phishing emails to target individuals in corporate settings have come out as well. For instance, earlier this year researchers from Barracuda Networks analyzed some 360,000 spear-phishing emails and found one in 10 involved sex-themed blackmail.
Barracuda found that the subject lines on a majority of sextortion emails contained some form of security alert and often included the victim's email address or password, too.
Though sextortion scams are twice as likely as business email scams in a corporate setting, they are often under-reported because of the intentionally embarrassing and sensitive nature of the content, Barracuda discovered. IT teams often are unaware of these attacks because employees don't report them regardless of whether they paid the demanded ransom.
For enterprises, the increase in sextortion and other scams highlight the need for strong email security controls, Haley says. "If these threats do not hit the end users' mailbox, then they do not become an issue," he notes. "Additionally, organizations need to educate their employees on the existence of these threats so they do not get fooled."