Gateway Server Memory Analysis: Process Injection & Lateral Pivot
| Report ID | SIR-2026-06-23-02 | Classification | Simulated / Training Environment |
| Analyst | F. Nanos | Date of Report | 2026-06-23 |
| Severity | Critical | Status | Closed (Contained) |
| Affected Asset | 1x DMZ gateway server (memory capture) | ||
1. Executive Summary
A memory capture from a DMZ gateway server was analyzed to reconstruct a full attack chain following lateral movement onto the host. The investigation traced execution from remote-service arrival through a disguised loader and dropper, into process injection against a legitimate system utility, and identified an active outbound RDP connection at time of capture indicating further lateral movement toward a second host. The engagement demonstrates that a single memory snapshot can resolve both "what happened on this host" and "where the threat actor went next" without requiring log data or a second host's evidence.
2. Scope & Methodology
Analysis was performed against pre-generated Volatility 3 plugin output derived from a full memory capture, prioritizing prefetched results over re-running plugins directly against the raw image given its size. Investigation followed a fixed sequence: process tree reconstruction, command-line recovery, code-injection detection, then network-connection review, a sequence chosen to move from "how did this start" through "what is the payload" to "where did it go."
# Volatility 3 plugin output review (prefetched)
cut -f1-3,11-13 pstree.txt
grep -A1 "<PID>" cmdline.txt
grep -A5 "^<PID>\s" malfind.txt
grep "<port>" netscan.txt
# Equivalent live commands, if run directly against the capture:
vol -f <capture> windows.pstree
vol -f <capture> windows.cmdline
vol -f <capture> windows.malfind
vol -f <capture> windows.netscan3. Technical Findings
3.1 Arrival & Execution Chain
Process tree reconstruction confirmed arrival via a remote service-execution mechanism, consistent with lateral movement tooling identified at an earlier stage of the wider campaign. The chain descended through a command shell into a signed Windows utility invoked with attacker-controlled arguments pointing at a disguised DLL dropped into a plausible system path, then a further renamed dropper delivered into a user's Downloads directory.
3.2 Living-off-the-Land Execution
Command-line recovery confirmed the initial attacker-controlled file was executed via a signed-binary-proxy pattern (a trusted system utility invoked against an attacker DLL with an exported function name), a widely used technique for evading application allow-listing based on the executing process's identity rather than its actual behavior.
3.3 Process Injection
The delivery chain terminated at injection into a legitimate, unremarkable system application selected specifically for its innocuous, expected-to-be-running nature. Memory-region analysis identified a writable-and-executable memory region within that process not backed by any file mapped from disk, the defining signature of injected code. A second, smaller candidate region present in the same process was assessed as a loader stub based on its substantially smaller committed size, with the larger region identified as the actual payload.
3.4 Lateral Pivot in Progress
Network-connection state captured at the time of acquisition showed an established outbound RDP connection originating from the same process tree as the injected payload, directed at a second internal host. This is assessed as an active lateral-movement pivot in progress at the moment of capture, identifying the likely next-affected asset without requiring evidence from that host directly.
4. Indicators of Compromise
| Type | Indicator | Context |
|---|---|---|
| Disguised DLL | [redacted, masquerading as Windows Update component] | Initial loader, dropped in system path |
| Renamed dropper | [redacted, masquerading as update/security tool] | Delivered to user Downloads directory |
| Injection target | Legitimate system utility (notepad-class process) | Injection host process |
| Shellcode signature | 0xFC opening byte (position-independent code marker) | Consistent with common post-exploitation frameworks |
| Pivot destination | [redacted internal IP]:3389 | Active RDP connection at capture time |
5. MITRE ATT&CK Mapping
| Technique ID | Technique | Tactic |
|---|---|---|
| T1021.002 / T1570 | Remote Services / Lateral Tool Transfer | Lateral Movement |
| T1218.011 | Signed Binary Proxy Execution (Rundll32) | Defense Evasion |
| T1036.005 | Masquerading | Defense Evasion |
| T1055 | Process Injection | Defense Evasion, Privilege Escalation |
| T1021.001 | Remote Services (RDP) | Lateral Movement |
6. Recommendations
- Deploy endpoint detection for signed-binary-proxy execution patterns, particularly command-line invocations combining a trusted system utility with attacker-supplied DLL and function-name arguments.
- Alert on writable-and-executable memory regions in common target processes not backed by a mapped file on disk, a reliable signature of code injection.
- Restrict and monitor outbound RDP from servers that should not require it in normal operation, given its use here as a lateral-movement channel.
- Retain memory-capture capability as a standing incident-response readiness measure. This investigation would not have been possible from disk or log artifacts alone.
7. Investigator's Notes
Determining the correct endpoint of the delivery chain required care: the deepest process in the process tree was not the correct answer, since child processes spawned from the injected process represent the threat actor operating from an established foothold, a conceptually distinct phase from how that foothold was established. The delivery chain is assessed to terminate at the injection target itself. This distinction, between the mechanism that delivers a payload and the activity conducted afterward from within it, is now treated as a standing consideration whenever chain-of-execution findings are documented.