New BEC cyberattacks use phishing with a legit Dropbox hyperlink as a lure for malware and credentials theft.
Risk actors have added a brand new wrinkle to conventional enterprise e mail compromise cyberattacks. Name it BEC 3.0 — phishing assaults that bury the hook in legit internet providers like Dropbox.
Avanan, a unit of Examine Level Software program, has tracked a current instance of this assault household, during which hackers created free Dropbox accounts to seize credentials or cover malware in legitimate-looking, contextually related paperwork similar to potential workers’ resumes.
The assault, the safety agency found, began with the actors sharing a PDF of somebody’s resume through Dropbox. The goal can’t view the doc until they Add To Dropbox. The hyperlink from Dropbox appeared legit, making the exploit tougher to identify.
The phishing exploit entails these steps:
- First, a consumer clicks the hyperlink in a legit notification from Dropbox to a resume and accesses a web page hosted on the file-sharing service.
- The consumer should then enter their e mail account and password to view the doc. Which means the menace actors have entry to e mail addresses and passwords.
On this web page hosted on Dropbox, customers are requested to enter their e mail account and password to view the doc, giving menace actors consumer credentials.
As soon as a consumer enters their credentials, they’re directed to a faux Microsoft OneDrive hyperlink. By clicking on the hyperlink, customers are given a malicious obtain.
“We’ve seen hackers do lots of BEC assaults,” Jeremy Fuchs, a cybersecurity researcher/analyst at Avanan, stated in a report on the assault. “These assaults have a number of variations, however typically they attempt to spoof an govt or companion to get an finish consumer to do one thing they don’t wish to do (like pay an bill to the flawed place),” he stated.
SEE: One other hide-the-malware assault focuses on DNS (TechRepublic)
“Leveraging legit web sites to host malicious content material is a surefire technique to get into the inbox,” he stated. “Most safety providers will take a look at the sender — on this case, Dropbox — and see that it’s legit and settle for the message. That’s as a result of it’s legit,” he added.
Avanan stated stopping these stealth assaults requires quite a few defensive steps, together with scanning for malicious recordsdata in Dropbox and hyperlinks in paperwork, in addition to changing hyperlinks within the e mail physique and inside attachments. The important thing to training towards these social engineering assaults is context, in accordance with Fuchs: “Are resumes sometimes despatched through Dropbox? If not, it might be a cause to contact the unique sender and double-check. If they’re, take it one step additional. Once you log into Dropbox, do I’ve to log in once more with my e mail?”
Avanan stated the researchers reached out to Dropbox on Might 15 to tell them of this assault and analysis.
Linktree additionally used to seize credentials
Earlier this month, Avanan found an identical hack utilizing the social media reference touchdown web page Linktree, which is hosted on websites like Instagram and TikTok. Much like the Dropbox assaults, hackers created legit Linktree pages to host malicious URLs to reap credentials.
The attackers despatched targets spoofed Microsoft OneDrive or SharePoint notifications {that a} file has been shared with them, instructing them to open the file, in accordance with Avanan. Finally, the consumer is redirected to a faux Workplace 365 login web page, the place they’re requested to enter their credentials, the place their credentials are stolen.
“[Users] ought to suppose: Why would this particular person ship me a doc through Linktree? More than likely, that wouldn’t be the case. That’s all part of safety consciousness — understanding if an e mail or course of appears logical,” stated Fuchs.
In these instances, the agency means that recipients:
- At all times test the sender’s deal with earlier than replying to an e mail.
- Cease and suppose if the medium getting used to ship a file is typical.
- When logging right into a web page, double-check the URL to see if it’s Microsoft or one other legit website.
BEC assaults utilizing legit websites might escalate this yr
Fuchs stated there are not any apparent visible cues to tip off assault recipients to BEC exploits. “Though in case you have been to signal into the Dropbox web page, you’d see that there’s a OneDrive emblem and hyperlink,” he stated. “Eagle-eyed customers ought to discover that discrepancy and suppose—why would there be two competing providers on one web page?,” he added.
He predicted that these assaults will escalate. “Any common service that’s legit can probably be used as a car to ship any such malicious exercise. That’s why we anticipate it to take off within the close to future,” he stated, including that the exploit has been used tens of hundreds of occasions. “We imagine this may actually take off in quantity within the second half of the yr,” he stated.
