Cybersecurity researchers have disclosed particulars of a brand new phishing marketing campaign that conceals malicious payloads by abusing hyperlink wrapping companies from Proofpoint and Intermedia to bypass defenses.
“Hyperlink wrapping is designed by distributors like Proofpoint to guard customers by routing all clicked URLs by a scanning service, permitting them to dam identified malicious locations in the mean time of click on,” the Cloudflare Electronic mail Safety workforce stated.
“Whereas that is efficient in opposition to identified threats, assaults can nonetheless succeed if the wrapped hyperlink hasn’t been flagged by the scanner at click on time.”
The exercise, noticed during the last two months, as soon as once more illustrates how menace actors discover other ways to leverage reliable options and trusted instruments to their benefit and carry out malicious actions, on this case, redirecting victims to Microsoft 365 phishing pages.
It is noteworthy that the abuse of hyperlink wrapping includes the attackers gaining unauthorized entry to electronic mail accounts that already use the function inside a corporation, in order that any electronic mail message containing a malicious URL despatched from that account is robotically rewritten with the wrapped hyperlink (e.g., urldefense.proofpoint[.]com/v2/url?u=
One other vital side issues what Cloudflare calls “multi-tiered redirect abuse,” by which the menace actors first cloak their malicious hyperlinks utilizing a URL shortening service like Bitly, after which ship the shortened hyperlink in an electronic mail message through a Proofpoint-secured account, inflicting it to be obscured a second time.
This conduct successfully creates a redirection chain, the place the URL passes by two ranges of obfuscation – Bitly and Proofpoint’s URL Protection – earlier than taking the sufferer to the phishing web page.
Within the assaults noticed by the net infrastructure firm, the phishing messages masquerade as voicemail notifications, urging recipients to click on on a hyperlink to hearken to them, finally directing them to a bogus Microsoft 365 phishing web page designed to seize their credentials.
Alternate an infection chains make use of the identical method in emails that notify customers of a supposed doc acquired on Microsoft Groups and trick them into clicking on booby-trapped hyperlinks.
A 3rd variation of those assaults impersonates Groups in emails, claiming that they’ve unread messages and that they’ll click on on the “Reply in Groups” button embedded within the messages to redirect them to credential harvesting pages.
“By cloaking malicious locations with reliable urldefense[.]proofpoint[.]com and url[.]emailprotection URLs, these phishing campaigns’ abuse of trusted hyperlink wrapping companies considerably will increase the chance of a profitable assault,” Cloudflare stated.
The event comes amid a spike in phishing assaults that weaponize Scalable Vector Graphics (SVG) recordsdata to get round conventional anti-spam and anti-phishing protections and provoke multi-stage malware infections.
“Not like JPEG or PNG recordsdata, SVG recordsdata are written in XML and help JavaScript and HTML code,” the New Jersey Cybersecurity and Communications Integration Cell (NJCCIC) stated final month. “They will include scripts, hyperlinks, and interactive components, which could be exploited by embedding malicious code inside innocent SVG recordsdata.”
Phishing campaigns have additionally been noticed embedding pretend Zoom videoconferencing hyperlinks in emails that, when clicked, set off a redirection chain to a pretend web page that mimics a realistic-looking interface, after which they’re served a “assembly connection timed out” message and brought to a phishing web page that prompts them to enter their credentials to rejoin the assembly.
“Sadly, as an alternative of ‘rejoining,’ the sufferer’s credentials together with their IP tackle, nation, and area are exfiltrated through Telegram, a messaging app infamous for ‘safe, encrypted communications,’ and inevitably despatched to the menace actor,” Cofense stated in a current report.
