An ongoing risk marketing campaign dubbed VEILDrive has been noticed benefiting from professional companies from Microsoft, together with Groups, SharePoint, Fast Help, and OneDrive, as a part of its modus operandi.
“Leveraging Microsoft SaaS companies — together with Groups, SharePoint, Fast Help, and OneDrive — the attacker exploited the trusted infrastructures of beforehand compromised organizations to distribute spear-phishing assaults and retailer malware,” Israeli cybersecurity firm Hunters mentioned in a brand new report.
“This cloud-centric technique allowed the risk actor to keep away from detection by standard monitoring techniques.”
Hunters mentioned it found the marketing campaign in September 204 after it responded to a cyber incident concentrating on a important infrastructure group in america. It didn’t disclose the title of the corporate, as a substitute giving it the designation “Org C.”
The exercise is believed to have commenced a month prior, with the assault culminating within the deployment of a Java-based malware that employs OneDrive for command-and-control (C2).
The risk actor behind the operation is alleged to have despatched Groups messages to 4 staff of Org C by impersonating an IT staff member and requesting distant entry to their techniques through the Fast Help software.
What made this preliminary compromise methodology stand out is that the attacker utilized a consumer account belonging to a possible prior sufferer (Org A), somewhat than creating a brand new account for this goal.
“The Microsoft Groups messages acquired by the focused customers of Org C had been made attainable by Microsoft Groups’ ‘Exterior Entry‘ performance, which permits One-on-One communication with any exterior group by default,” Hunters mentioned.
Within the subsequent step, the risk actor shared through the chat a SharePoint obtain hyperlink to a ZIP archive file (“Client_v8.16L.zip”) that was hosted on a unique tenant (Org B). The ZIP archive got here embedded with, amongst different recordsdata, one other distant entry software named LiteManager.
The distant entry gained through Fast Help was then used to create scheduled duties on the system to periodically execute the LiteManager distant monitoring and administration (RMM) software program.
Additionally downloading is a second ZIP file (“Cliento.zip”) utilizing the identical methodology that included the Java-based malware within the type of a Java archive (JAR) and the whole Java Growth Equipment (JDK) to execute it.
The malware is engineered to hook up with an adversary-controlled OneDrive account utilizing hard-coded Entra ID (previously Azure Lively Listing) credentials, utilizing it as a C2 for fetching and executing PowerShell instructions on the contaminated system by utilizing the Microsoft Graph API.
It additionally packs in a fallback mechanism that initializes an HTTPS socket to a distant Azure digital machine, which is then utilized to obtain instructions and execute them below the context of PowerShell.
This isn’t the primary time the Fast Help program has been used on this method. Earlier this Could, Microsoft warned {that a} financially motivated cybercriminal group often known as Storm-1811 misused Fast Help options by pretending to be IT professionals or technical help personnel to achieve entry and drop Black Basta ransomware.
The event additionally comes weeks after the Home windows maker mentioned it has noticed campaigns abusing professional file internet hosting companies like SharePoint, OneDrive, and Dropbox as technique of evading detection.
“This SaaS-dependent technique complicates real-time detection and bypasses standard defenses,” Hunters mentioned. “With zero obfuscation and well-structured code, this malware defies the everyday development of evasion-focused design, making it unusually readable and simple.”
