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Lyceum, also known as Hexane, SiameseKitten, Spirlin, and Storm-0133, is an Iranian state-linked cyber-espionage threat actor widely assessed as a subgroup or closely associated cluster within the broader OilRig ecosystem and linked to Iran’s Ministry of Intelligence and Security (MOIS). The actor has been associated with targeted intrusions against Israeli organizations and has shown operational and technical overlap with other Iranian intrusion sets, including MuddyWater. Reporting also notes coordination or resource overlap within the Iranian intelligence cyber ecosystem. Lyceum is associated with modular .NET-based malware and post-compromise frameworks, including low-confidence overlaps with the Cavern framework and the HollowGraph malware component. HollowGraph demonstrates tradecraft centered on covert command-and-control through compromised Microsoft 365 mailboxes and Microsoft Graph API calendar abuse, with a secondary DNS-based credential refresh channel. Although attribution of HollowGraph directly to Lyceum remains low confidence, the technical similarities cited include comparable modular architecture, plugin-loading behavior, and command structure. The actor’s activity is consistent with focused espionage operations rather than financially motivated crime. Observed tradecraft includes use of compromised cloud identities, persistence through OAuth or application credentials, covert command-and-control over trusted services, data exfiltration, reconnaissance, and post-exploitation within victim environments. Broader overlaps tied to the Cavern ecosystem include targeting of government entities and IT providers, supply-chain-style pivoting through service providers, network and directory reconnaissance, file operations, and tunneling or proxy capabilities. Lyceum should be understood as part of the Iranian intelligence-aligned intrusion landscape, with operations oriented toward stealthy long-term access and intelligence collection.
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Who, where, and (when attributed) which flag flies behind the operation. Pulled from open-source reporting and Mallory's analyst review.
Sectors the actor has been observed targeting.
Geographies tied to known operations.
Attributed origin per open-source reporting.
48 distinct techniques observed across reporting, grouped by tactic. Hover any cell for the evidence excerpt; click through for MITRE's full description.
20 malware families attributed to this actor across reporting.
15 additional families tracked in Mallory.
1 CVE this actor has used in observed campaigns. 1 of them exploited in the wild.
71 indicators attributed to this actor: domains, IPs, hashes, and other artifacts pulled from reporting. View more in app.
20 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Likely operator of the Cavern framework and associated with the HollowGraph backdoor used to compromise Microsoft 365 mailboxes, hide C2 in mailbox calendars, maintain persistence via Microsoft Graph API and DNS, and target Israeli organizations.
Mentioned as a possible but low-confidence attribution link based on malware similarities to the Cavern framework; no definitive operational attribution is made in the content.
Iran-linked subgroup discussed as a low-confidence attribution candidate for the HollowGraph activity based on technical similarities.
Referenced as an overlapping or related Iran-linked threat actor in connection with Cavern Manticore; no direct attribution by Group-IB.
Match sector + geo + tech-stack targeting against your real footprint.
Every observed MITRE ATT&CK technique, grouped by tactic.
Families this actor is known to deploy, with IOCs and behavior.
CVEs this actor has used in known campaigns.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Domains, IPs, and hashes tied to this actor, refreshed continuously.