Russian spies take their half-click email attack from Zimbra to Outlook

The Russian espionage crew that turned simply reading an email into a security risk has expanded beyond Zimbra, with Proofpoint saying it's now pulling the same half-click trick against Microsoft Outlook Web Access. Proofpoint says the cyber group it tracks as TA488, or "Laundry Bear," began exploiting CVE-2026-42897, a cross-site scripting flaw in the Outlook Web Access (OWA) component of on-premises Exchange Server, a day before researchers and government agencies exposed the group's abuse of a zero-day in Zimbra Collaboration Suite. Unlike conventional phishing attacks, this one doesn't depend on persuading the victim to follow a link or download a file. If a target opens the booby-trapped message in OWA, the browser executes attacker-controlled JavaScript inside the victim's authenticated mail session. Exchange Online is not affected. According to Proofpoint, TA488 abused the OWA flaw to target government organizations in the US and Europe, along with telecommunications, financial services, hospitality, and aerospace companies. The researchers said the unusually broad campaign may have been intended to hide among the background noise of everyday email traffic rather than the tightly focused operations more commonly associated with espionage groups. "TA488 appears to demonstrate interest in a wide range of sectors while maintaining priorities for intelligence collection against government and defense," Proofpoint said. "Lure themes remain generic and unremarkable, so the target is more inclined to open and skim the email but ultimately overlook it." Instead of dropping conventional malware onto the endpoint, the attackers deploy a browser implant dubbed OWAReaper that lives entirely inside OWA. Proofpoint says it leaves virtually no host artifacts, communicates over two command-and-control channels, supports multiple methods of exfiltrating data, and survives browser restarts, password changes, and even a complete device rebuild because the foothold resides in the compromised mailbox rather than on Windows itself. CVE-2026-42897 isn't making its debut on The Register. Microsoft disclosed the bug in May following reports that attackers were using it in the wild. Proofpoint's latest report fills in more of the picture, showing the activity formed part of a broader espionage campaign rather than isolated exploitation. Proofpoint believes TA488 may actually have been exploiting the flaw as a zero-day, citing attacker infrastructure that dates back to March, roughly two months before Microsoft's out-of-band patch. If accurate, that would suggest the campaign was underway well before defenders knew there was a vulnerability to fix. "If this is the case, the combined improvement of the malware and the exploit development against a harder target in Outlook Web Access signal a leap in capability by TA488," Proofpoint said. Microsoft did not immediately respond to The Register's questions, but if Proofpoint's assessment holds up, TA488 isn't just recycling an old trick. It's refining one that has already proven capable of slipping past one of the oldest pieces of security advice in the book: don't click suspicious links. (R)