Techniques › T1041 › AN0991
AN0991 Analytic 0991
ESXi · attack.mitre.org · ATT&CK Enterprise v19.2
<p>Detects VMs sending outbound traffic through non-standard services or to unknown destinations. Exfiltration over reverse shells tunneled via VMkernel or custom payloads routed via hostd/vpxa.</p>
- Detects
- T1041 Exfiltration Over C2 Channel
- Part of
- DET0348 Detection Strategy for Exfiltration Over C2 Channel
Log sources and channels
Exactly as MITRE states them in x_mitre_log_source_references. Where a channel is vague, it is vague in the source; kevmap does not tidy it.
| Log source | Channel | Data component |
|---|---|---|
| esxi:vpxa | connection attempts and data transmission logs | DC0078 Network Traffic Flow |
| esxi:vmkernel | network stack module logs | DC0085 Network Traffic Content |
| esxi:syslog | guest OS outbound transfer logs | DC0055 File Access |
Mutable elements
Parameters MITRE marks as environment-specific. These are the knobs you are expected to tune; they are why an analytic is not a rule.
| Field | Description |
|---|---|
GuestOSAllowList | Limit detection to sensitive or externally-exposed VMs handling confidential data. |
TransferSizeThresholdMB | Minimum outbound transfer size before flagging anomalous C2-based exfiltration. |
ProtocolAllowList | Define expected protocols for outbound data (e.g., disallow FTP/SCP over high ports). |
KEV CVEs whose mapped technique this analytic detects
| CVE | Vendor / product | State |
|---|---|---|
| CVE-2018-4878 | Adobe Flash Player | Mapped |
| CVE-2019-0604 | Microsoft SharePoint | Mapped |
| CVE-2019-18935 | Progress Telerik UI for ASP.NET AJAX | Mapped |
| CVE-2023-1389 | TP-Link Archer AX21 | Mapped |
| CVE-2023-2868 | Barracuda Networks Email Security Gateway (ESG) Appliance | Mapped |
| CVE-2023-38831 | RARLAB WinRAR | Mapped |
| CVE-2023-5631 | Roundcube Webmail | Mapped |
| CVE-2024-27443 | Synacor Zimbra Collaboration Suite (ZCS) | Mapped |
| CVE-2024-4577 | PHP Group PHP | Mapped |
| CVE-2024-55550 | Mitel MiCollab | Mapped |
| CVE-2025-32756 | Fortinet Multiple Products | Mapped |
| CVE-2025-33053 | Microsoft Windows | Mapped |