Microsoft successfully detected and disabled attack activity abusing OneDrive by a previously undocumented Lebanon-based activity group Microsoft Threat Intelligence Center (MSTIC) tracks as POLONIUM. The associated indicators and tactics were used by the OneDrive team to improve detection of attack activity and disable offending actor accounts. To further address this abuse, Microsoft has suspended more than 20 malicious OneDrive applications created by POLONIUM actors, notified affected organizations, and deployed a series of security intelligence updates that will quarantine tools developed by POLONIUM operators. Our goal with this blog is to help deter future activity by exposing and sharing the POLONIUM tactics with the community at large.
MSTIC assesses with high confidence that POLONIUM represents an operational group based in Lebanon. We also assess with moderate confidence that the observed activity was coordinated with other actors affiliated with Iran’s Ministry of Intelligence and Security (MOIS), based primarily on victim overlap and commonality of tools and techniques. Such collaboration or direction from Tehran would align with a string of revelations since late 2020 that the Government of Iran is using third parties to carry out cyber operations on their behalf, likely to enhance Iran’s plausible deniability.