Detecting Process Hollowing Technique

What it does

When your agent uses it

• Investigating a legitimate-looking process (svchost.exe
• Rundll32.exe) suspected of hosting injected code via NtUnmapViewOfSection

Example prompts

• “/detecting-process-hollowing-technique”

Requirements

• Python 3

Workflow steps

7 steps, taken from the first numbered list in SKILL.md.

1. 1Understand Hollowing Mechanics: Process hollowing involves creating a legitimate process in suspended state, unmapping its memory, writing…
2. 2Monitor Suspended Process Creation: Hunt for processes created with CREATE_SUSPENDED flag followed by memory writes and thread resumption.
3. 3Detect Memory Section Anomalies: Identify processes where the in-memory image differs from the on-disk binary (image mismatch).
4. 4Analyze Parent-Child Process Trees: Flag processes whose behavior does not match their binary name (e.g., svchost.exe making unusual…
5. 5Check Process Integrity: Compare process memory sections against the legitimate binary on disk.
6. 6Correlate with Network Activity: Hollowed processes often establish C2 connections - correlate suspicious process behavior with network…
7. 7Document and Contain: Report findings, isolate affected endpoints, and update detection rules.

What it can do on your machine

Read from SKILL.md and the folder at commit 54a7988. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships 2 files in scripts/ (Python), which the agent can run.

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Detecting Process Hollowing Technique loads about 1.2k tokens when it runs, and up to ~3.3k if it reads all its reference files. Until then it costs about 107 tokens; SKILL.md has 412 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~107

When it runs · the whole SKILL.md, loaded when a task matches

~1.2k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~3.3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from mukul975/Anthropic-Cybersecurity-Skills at commit 54a7988, republished under its Apache-2.0 licence (© mukul975). 412 words, ~1,226 tokens.

name

detecting-process-hollowing-technique

description

Detect process hollowing (MITRE T1055.012) by analyzing memory-mapped sections, hollowed process indicators, and parent-child anomalies using EDR telemetry, Volatility's malfind plugin, pe-sieve, Hollows Hunter, and Sysmon Event ID 25. Use when investigating a legitimate-looking process (svchost.exe, explorer.exe, rundll32.exe) suspected of hosting injected code via NtUnmapViewOfSection.

domain

cybersecurity

subdomain

threat-hunting

tags

threat-hunting, mitre-attack, process-hollowing, process-injection, edr, t1055, proactive-detection

version

1.0

author

mahipal

license

Apache-2.0

d3fend_techniques

Platform Monitoring, Process Code Segment Verification, Segment Address Offset Randomization, Process Analysis, Application Hardening

nist_csf

DE.CM-01, DE.AE-02, DE.AE-07, ID.RA-05

mitre_attack

T1046, T1057, T1082, T1083, T1055

Hunt ID: TH-HOLLOW-[DATE]-[SEQ]
Technique: T1055.012
Hollowed Process: [Process name and PID]
Original Binary: [Expected on-disk path]
Parent Process: [Parent name and PID]
Memory Mismatch: [Yes/No]
Suspicious APIs: [NtUnmapViewOfSection, WriteProcessMemory, etc.]
Network Activity: [C2 connections if any]
Host: [Hostname]
User: [Account context]
Risk Level: [Critical/High/Medium/Low]

© mukul975, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 7 other files (scripts, references, assets) in skills/detecting-process-hollowing-technique of mukul975/Anthropic-Cybersecurity-Skills.

• SKILL.md
• LICENSE
• assets/template.md
• references/api-reference.md
• references/standards.md
• references/workflows.md
• scripts/agent.py
• scripts/process.py

Open the folder on GitHubat commit 54a7988