ctipilot.ch

OilRig

actor · actor:oilrig single-source

Iran-nexus (MOIS-linked) cyber-espionage actor active since ~2014 against Middle East government, energy, telecom and IT targets, known for cloud-service-abusing C2 (Microsoft Graph, OneDrive) and DNS-tunnelling tooling. Kaspersky associates the Cavern / Project CAV3RN framework (tracked as Cavern Manticore by Check Point, HOLLOWGRAPH by Group-IB) with OilRig with LOW confidence, noting behavioural overlap but no direct code reuse or infrastructure overlap (Kaspersky, 2026-07-21).

Aliases: APT34, Helix Kitten, Evasive Serpens, Hazel Sandstorm

Coverage timeline
2
first 2026-07-09 → last 2026-07-22
Peak priority
notable
2 notable
Sources cited
2
2 hosts
Sections touched
2
active-threats, updates
Co-occurring entities
4
see Related entities below
ATT&CK techniques
8
pinned v19.1 · see below
2026-07-092 appearances2026-07-22

Hunting pivots

ATT&CK techniques
T1008T1071.004T1102.002T1573
Affected products
Microsoft 365Microsoft GraphMicrosoft Outlook
Tags
espionage ×2nation-state ×2cloudidentityiran-nexus

ATT&CK techniques

8 techniques observed across 2 entries — derived from entry metadata and body evidence, never asserted without a published entry behind it · pinned to MITRE ATT&CK v19.1 · compare on the matrix · Navigator layer (JSON)

Execution TA0002

T1574.001Hijack Execution Flow: DLL×1

Adversaries may abuse dynamic-link library files (DLLs) in order to achieve persistence, escalate privileges, and evade defenses. DLLs are libraries that contain code and data that can be simultaneously utilized by multiple programs. While DLLs are not malicious by nature, they can be abused through mechanisms such as side-loading, hijacking search order, and phantom DLL hijacking.

Evidence: 2026-07-09/cavern-manticore-iran-mois-modular-net-c2-anti-analysis · ATT&CK page ↗

Stealth TA0005

T1027Obfuscated Files or Information×1

Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses.

Evidence: 2026-07-09/cavern-manticore-iran-mois-modular-net-c2-anti-analysis · ATT&CK page ↗

T1574.001Hijack Execution Flow: DLL×1

Adversaries may abuse dynamic-link library files (DLLs) in order to achieve persistence, escalate privileges, and evade defenses. DLLs are libraries that contain code and data that can be simultaneously utilized by multiple programs. While DLLs are not malicious by nature, they can be abused through mechanisms such as side-loading, hijacking search order, and phantom DLL hijacking.

Evidence: 2026-07-09/cavern-manticore-iran-mois-modular-net-c2-anti-analysis · ATT&CK page ↗

T1620Reflective Code Loading×1

Adversaries may reflectively load code into a process in order to conceal the execution of malicious payloads. Reflective loading involves allocating then executing payloads directly within the memory of the process, vice creating a thread or process backed by a file path on disk (e.g., Shared Modules).

Evidence: 2026-07-09/cavern-manticore-iran-mois-modular-net-c2-anti-analysis · ATT&CK page ↗

Command and Control TA0011

T1008Fallback Channels×1

Adversaries may use fallback or alternate communication channels if the primary channel is compromised or inaccessible in order to maintain reliable command and control and to avoid data transfer thresholds.

Evidence: 2026-07-22/cavern-cav3rn-oilrig-attribution-dns-aaaa-c2-fallback · ATT&CK page ↗

T1071.004Application Layer Protocol: DNS×1

Adversaries may communicate using the Domain Name System (DNS) application layer protocol to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

Evidence: 2026-07-22/cavern-cav3rn-oilrig-attribution-dns-aaaa-c2-fallback · ATT&CK page ↗

T1102.002Web Service: Bidirectional Communication×1

Adversaries may use an existing, legitimate external Web service as a means for sending commands to and receiving output from a compromised system over the Web service channel. Compromised systems may leverage popular websites and social media to host command and control (C2) instructions. Those infected systems can then send the output from those commands back over that Web service channel. The return traffic may occur in a variety of ways, depending on the Web service being utilized. For example, the return traffic may take the form of the compromised system posting a comment on a forum, issuing a pull request to development project, updating a document hosted on a Web service, or by sending a Tweet.

Evidence: 2026-07-22/cavern-cav3rn-oilrig-attribution-dns-aaaa-c2-fallback · ATT&CK page ↗

T1219Remote Access Tools×1

An adversary may use legitimate remote access tools to establish an interactive command and control channel within a network. Remote access tools create a session between two trusted hosts through a graphical interface, a command line interaction, a protocol tunnel via development or management software, or hardware-level access such as KVM (Keyboard, Video, Mouse) over IP solutions. Desktop support software (usually graphical interface) and remote management software (typically command line interface) allow a user to control a computer remotely as if they are a local user inheriting the user or software permissions. This software is commonly used for troubleshooting, software installation, and system management. Adversaries may similarly abuse response features included in EDR and other defensive tools that enable remote access.

Evidence: 2026-07-09/cavern-manticore-iran-mois-modular-net-c2-anti-analysis · ATT&CK page ↗

T1573Encrypted Channel×1

Adversaries may employ an encryption algorithm to conceal command and control traffic rather than relying on any inherent protections provided by a communication protocol. Despite the use of a secure algorithm, these implementations may be vulnerable to reverse engineering if secret keys are encoded and/or generated within malware samples/configuration files.

Evidence: 2026-07-22/cavern-cav3rn-oilrig-attribution-dns-aaaa-c2-fallback · ATT&CK page ↗

Story timeline

  1. 2026-07-22Kaspersky corroborates the Cavern/HOLLOWGRAPH cluster, associates it (low confidence) with OilRig (APT34), and details a DNS AAAA-record C2 config-recovery fallback
    updatesA second vendor links the Outlook-calendar Graph C2 framework to OilRig (low confidence) and documents a DNS AAAA fallback that restores its cloud C2
  2. 2026-07-09Check Point: Iran MOIS-linked "Cavern Manticore" ships a modular .NET C2 that uses three compilation formats as an anti-analysis layer, delivered via SysAid RMM abuse
    active-threatsCavern Manticore's C2 splits across IL, Mixed-Mode and NativeAOT binaries to break RE toolchains — pushed through SysAid's legitimate deployment feature

Relationships explore in graph

Typed, source-stated connections from the entity registry — each edge cites the entry whose reporting establishes it.

related to

Where this entity is cited

  • active-threats1
  • updates1

Source distribution

  • research.checkpoint.com1 (50%)
  • securelist.com1 (50%)

Co-occurring entities

Derived — referenced by the same focused operational entries (weekly summaries and report roundups don't count); ×N counts the shared entries.

All cited sources (2)

Entries about OilRig (2)

2026-07-22 · view entry permalink →

NOTABLEupdateNATOB2

Kaspersky corroborates the Cavern/HOLLOWGRAPH cluster, associates it (low confidence) with OilRig (APT34), and details a DNS AAAA-record C2 config-recovery fallback

UPDATE · originally covered HOLLOWGRAPH: a Cavern-framework backdoor that turns a compromised Microsoft 365 calendar into a Graph-API dead-drop C2 (2026-07-21)

The HOLLOWGRAPH entry documented an Iran-linked backdoor that used Microsoft Graph and far-future Outlook calendar events as its command-and-control channel. Kaspersky GReAT has now published independent analysis of the same toolset — which Check Point tracks as "Cavern Manticore" — detailing a new communication module (AzureCommunication.dll) that replaces the earlier HTTP/WebSocket component with Microsoft Graph, exchanging RSA-OAEP-SHA256 + AES-256-GCM-encrypted commands and results as attachments inside far-future Outlook calendar events (a fixed 2050-05-13 window) keyed to a controller-generated agent ID (Kaspersky, 2026-07-21; Check Point Research, 2026-07-06).

The new element beyond prior reporting is a resilience layer: when Graph authentication or tenant validation fails, the module recovers replacement connection settings (TenantId, ClientId, ClientSecret, UserEmail) via DNS AAAA responses from attacker-controlled nameservers, encoding length markers and 14-byte chunks in specially formatted subdomains. On attribution, Kaspersky retains its low-confidence assessment that Project CAV3RN is associated with OilRig (APT34) — a link it first drew in a previous report — noting the new module shares behavioural patterns with previously reported OilRig tooling (Microsoft-hosted-service C2, attachment-based command exchange, a secondary cloud-C2 recovery mechanism) while explicitly identifying no direct code reuse or infrastructure overlap (Kaspersky, 2026-07-21). Treat the OilRig association as an analytic lead, not a settled attribution.

If Microsoft Graph authentication or tenant validation fails, the module attempts to retrieve replacement connection settings through DNS AAAA responses.

The new module shares several behavioral patterns with previously reported OilRig tooling, including the use of Microsoft-hosted services, attachment-based command exchange, and a secondary mechanism for restoring access to a cloud C2 channel.

Kaspersky (Securelist / GReAT) 2026-07-21
threat22 Jul 04:34Zmulti-sourceOpen finding ↗
Sources: Kaspersky (Securelist / GReAT) · Check Point Research

2026-07-09 · view entry permalink →

NOTABLENATOB3

Check Point: Iran MOIS-linked "Cavern Manticore" ships a modular .NET C2 that uses three compilation formats as an anti-analysis layer, delivered via SysAid RMM abuse

Check Point Research documented Cavern Manticore, an Iran MOIS-linked APT it assesses shares technical and infrastructure overlap with MuddyWater and OilRig's Lyceum subgroup, targeting Israeli government and IT-sector organisations (Check Point Research, 2026-07-06). Its namesake framework, Cavern, is a modular post-exploitation .NET C2 whose components are deliberately compiled into three different binary formats: pure IL-only .NET (the mhm.dll file-ops/DPAPI-decrypt module, db.dll SQL browser, ode.dll LDAP/AD-recon module), Mixed-Mode C++/CLI IL+native (the uxtheme.dll Cavern Agent core), and .NET 8 NativeAOT native-only (n-HTCommp.dll HTTPS/WebSocket transport, n-ten.dll network recon/SMB brute-force, n-sws.dll SOCKS5/WSS tunnel). The compilation-format diversity is itself the anti-analysis layer: each format demands a different reverse-engineering toolchain, and NativeAOT strips framework symbols and resolves security-sensitive P/Invoke calls (WNetAddConnection2, NetShareEnum, NetLocalGroupGetMembers) through runtime descriptor tables rather than the PE import table, hiding capability from import-based triage (Check Point Research, 2026-07-06).

Delivery is the transferable part: the actor abused SysAid's legitimate software-update/deployment feature — not a SysAid vulnerability — to push a WinDirStat DLL-sideloading package that loads the trojanized uxtheme.dll as the Cavern Agent, which exports 83 functions mimicking the real Windows theming library (82 empty stubs; the one live export, EnableThemeDialogTexture, is the C2 entry point) — a sandbox trap for automated analysis that only invokes default exports. Each loaded module is isolated in its own .NET AppDomain via a MarshalByRefObject proxy so modules can be unloaded cleanly after use, leaving minimal forensic residue; most samples score zero or near-zero on VirusTotal. ATT&CK: T1574.002 DLL Side-Loading, T1027 Obfuscated Files or Information (via compilation-format diversity), T1620 Reflective Code Loading (AppDomain-isolated modules), T1219 Remote Access Software (SysAid deployment abuse).

Cavern Manticore is an Iran MOIS (Ministry of Intelligence and Security)-linked actor, with links to the OilRig subgroup named Lyceum

the compilation format itself becomes the anti-analysis layer, since each of the three formats has to be reversed with a different toolchain

SysAid was not compromised, and no SysAid vulnerability was involved. The attacker had already gained access to the victim environment and abused a legitimate software-deployment feature

Check Point Research 2026-07-06
threat09 Jul 04:32Zsingle-sourceOpen finding ↗
Sources: Check Point Research