Files

231 lines
9.5 KiB
Python
Executable File

#!/usr/bin/env python3
"""
procmon_summary.py - condense a Procmon CSV export into a behavior summary.
Runs on the host against evidence exported from the analysis VM
(Procmon: File -> Save -> All events -> CSV). Stdlib only.
Usage:
python3 procmon_summary.py procmon.csv --process sample.exe
python3 procmon_summary.py procmon.csv --all # no process filter
python3 procmon_summary.py --self-test
--process takes a comma list of image names (case-insensitive). The summary
covers those processes plus every descendant found via "Process Create".
Without --process (or with --all) every process in the log is included.
Output sections: process tree, files written/renamed/deleted, registry writes
(persistence keys flagged), network endpoints, non-system image loads.
Pipe the output through scripts/ioc_extract.py to get defanged IOCs.
"""
import argparse
import csv
import io
import re
import sys
from collections import defaultdict, OrderedDict
PERSISTENCE_RE = re.compile(
r"CurrentVersion\\(Run|RunOnce|RunServices|Explorer\\(Shell Folders|User Shell Folders))"
r"|CurrentControlSet\\Services\\"
r"|Winlogon\\(Shell|Userinit|Notify)"
r"|Image File Execution Options"
r"|Windows\\CurrentVersion\\Policies\\Explorer\\Run"
r"|Schedule\\TaskCache"
r"|Office\\.*\\Security"
r"|AppInit_DLLs"
r"|Start Menu\\Programs\\Startup",
re.IGNORECASE,
)
SYSTEM_DIR_RE = re.compile(r"^[A-Z]:\\Windows\\", re.IGNORECASE)
PID_RE = re.compile(r"PID:\s*(\d+)")
CMD_RE = re.compile(r"Command line:\s*(.*?)(?:,\s*Current directory:|$)", re.DOTALL)
NEWFILE_RE = re.compile(r"OpenResult:\s*(Created|Overwritten|Superseded)")
def read_text(path):
"""Read exported evidence regardless of PowerShell's default encoding (UTF-16LE with BOM)."""
raw = open(path, "rb").read()
if raw.startswith((b"\xff\xfe", b"\xfe\xff")):
return raw.decode("utf-16", errors="replace")
return raw.decode("utf-8-sig", errors="replace")
def load(path):
return list(csv.DictReader(io.StringIO(read_text(path))))
def field(row, *names):
for n in names:
if n in row and row[n] is not None:
return row[n]
return ""
def build_tree(rows):
"""Return (children: pid -> [pid], info: pid -> (name, cmdline))."""
children = defaultdict(list)
info = {}
for r in rows:
op = field(r, "Operation")
if op == "Process Create":
m = PID_RE.search(field(r, "Detail"))
if not m:
continue
child = m.group(1)
parent = field(r, "PID")
children[parent].append(child)
cmd = CMD_RE.search(field(r, "Detail"))
# name the child from the created image path (the actor row's name is the parent)
created = field(r, "Path")
child_name = created.rsplit("\\", 1)[-1] if created else "?"
info.setdefault(child, [child_name or "?", cmd.group(1).strip() if cmd else ""])
elif op == "Process Start":
pid = field(r, "PID")
cmd = CMD_RE.search(field(r, "Detail"))
info[pid] = [field(r, "Process Name"), cmd.group(1).strip() if cmd else ""]
for r in rows: # fill names for processes seen only as actors
pid = field(r, "PID")
if pid and pid not in info:
info[pid] = [field(r, "Process Name"), ""]
elif pid in info and info[pid][0] == "?":
info[pid][0] = field(r, "Process Name")
return children, info
def descendants(seeds, children):
seen, stack = set(), list(seeds)
while stack:
p = stack.pop()
if p in seen:
continue
seen.add(p)
stack.extend(children.get(p, []))
return seen
def print_tree(pid, children, info, depth, out):
name, cmd = info.get(pid, ("?", ""))
out.append(f"{' ' * depth}{name} (PID {pid})" + (f" {cmd}" if cmd else ""))
for c in children.get(pid, []):
print_tree(c, children, info, depth + 1, out)
def summarize(rows, process_names=None):
children, info = build_tree(rows)
if process_names:
wanted = {n.lower() for n in process_names}
seeds = [pid for pid, (name, _) in info.items() if name.lower() in wanted]
scope = descendants(seeds, children)
roots = seeds
else:
scope = set(info)
all_children = {c for cs in children.values() for c in cs}
roots = [p for p in info if p not in all_children]
files = OrderedDict()
renames, deletes = OrderedDict(), OrderedDict()
reg = OrderedDict()
net = OrderedDict()
loads = OrderedDict()
counts = defaultdict(int)
for r in rows:
pid = field(r, "PID")
if pid not in scope:
continue
op, path, detail = field(r, "Operation"), field(r, "Path"), field(r, "Detail")
who = f"{field(r, 'Process Name')}:{pid}"
counts[who] += 1
if op == "CreateFile" and NEWFILE_RE.search(detail):
files.setdefault(path, who)
elif op == "WriteFile":
files.setdefault(path, who)
elif op == "SetRenameInformationFile":
m = re.search(r"FileName:\s*(.*)$", detail)
renames.setdefault(f"{path} -> {m.group(1) if m else '?'}", who)
elif op in ("SetDispositionInformationFile", "SetDispositionInformationEx") and "True" in detail:
deletes.setdefault(path, who)
elif op in ("RegSetValue", "RegDeleteValue", "RegDeleteKey") or (
op == "RegCreateKey" and "REG_CREATED_NEW_KEY" in detail
):
data = ""
m = re.search(r"Data:\s*(.*)$", detail)
if m:
data = m.group(1)
reg.setdefault(f"{op} {path}" + (f" = {data}" if data else ""), who)
elif op.startswith(("TCP", "UDP")) and "->" in path:
dst = path.split("->", 1)[1].strip()
net.setdefault(f"{op.split()[0]} {dst}", who)
elif op == "Load Image" and not SYSTEM_DIR_RE.match(path):
loads.setdefault(path, who)
out = [f"# Procmon summary ({len(rows)} events, {len(scope)} processes in scope)", "", "## Process tree"]
for root in roots:
print_tree(root, children, info, 0, out)
def section(title, items, limit=200):
out.extend(["", f"## {title} ({len(items)})"])
for i, (k, who) in enumerate(items.items()):
if i >= limit:
out.append(f"... {len(items) - limit} more")
break
out.append(f"- {k} [{who}]")
section("Files created/written", files)
section("Files renamed", renames)
section("Files deleted", deletes)
out.extend(["", f"## Registry writes ({len(reg)})"])
for k, who in reg.items():
flag = " <-- PERSISTENCE" if PERSISTENCE_RE.search(k) else ""
out.append(f"- {k} [{who}]{flag}")
section("Network endpoints", net)
section("Image loads outside C:\\Windows", loads)
out.extend(["", "## Event count per process"])
for who, n in sorted(counts.items(), key=lambda x: -x[1])[:20]:
out.append(f"- {who}: {n}")
return "\n".join(out)
SELF_TEST_CSV = '''"Time of Day","Process Name","PID","Operation","Path","Result","Detail"
"1","explorer.exe","100","Process Create","C:\\Users\\Public\\sample.exe","SUCCESS","PID: 200, Command line: ""C:\\Users\\Public\\sample.exe"" /install"
"2","sample.exe","200","Process Start","","SUCCESS","Parent PID: 100, Command line: ""C:\\Users\\Public\\sample.exe"" /install, Current directory: C:\\Users\\Public\\"
"3","sample.exe","200","CreateFile","C:\\Users\\Bob\\AppData\\Roaming\\svc.exe","SUCCESS","Desired Access: Generic Write, OpenResult: Created"
"4","sample.exe","200","RegSetValue","HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\svc","SUCCESS","Type: REG_SZ, Length: 60, Data: C:\\Users\\Bob\\AppData\\Roaming\\svc.exe"
"5","sample.exe","200","TCP Connect","host.local:49700 -> 203.0.113.5:443","SUCCESS","Length: 0"
"6","sample.exe","200","Process Create","C:\\Windows\\System32\\cmd.exe","SUCCESS","PID: 300, Command line: cmd.exe /c del sample.exe"
"7","cmd.exe","300","SetDispositionInformationFile","C:\\Users\\Public\\sample.exe","SUCCESS","Delete: True"
"8","chrome.exe","999","WriteFile","C:\\Users\\Bob\\cache.dat","SUCCESS","Offset: 0"
'''
def self_test():
rows = list(csv.DictReader(io.StringIO(SELF_TEST_CSV)))
out = summarize(rows, ["sample.exe"])
assert "cmd.exe (PID 300)" in out and " cmd.exe" in out, "child not nested under sample"
assert "svc.exe" in out and "PERSISTENCE" in out, "persistence run key not flagged"
assert "203.0.113.5:443" in out, "network endpoint missing"
assert "cache.dat" not in out, "unrelated process leaked into scope"
assert "Files deleted (1)" in out, "deletion missing"
print("self-test OK")
def main():
ap = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
ap.add_argument("csv", nargs="?")
ap.add_argument("--process", help="comma list of image names to scope on (plus descendants)")
ap.add_argument("--all", action="store_true", help="include every process")
ap.add_argument("--self-test", action="store_true")
a = ap.parse_args()
if a.self_test:
return self_test()
if not a.csv:
ap.error("csv path required")
names = None if a.all or not a.process else [n.strip() for n in a.process.split(",")]
print(summarize(load(a.csv), names))
if __name__ == "__main__":
main()