fix: normalize SSH bash CMD lines to service=ssh, event_type=command

The SSH honeypot logs commands via PROMPT_COMMAND logger as:
  <14>1 ... bash - - -  CMD uid=0 pwd=/root cmd=ls
These lines had service=bash and event_type=-, so the attacker worker
never recognized them as commands. Both the collector and correlation
parsers now detect the CMD pattern and normalize to service=ssh,
event_type=command, with uid/pwd/command in fields.
This commit is contained in:
2026-04-14 01:54:36 -04:00
parent 7ecb126c8e
commit a6c7cfdf66
4 changed files with 89 additions and 0 deletions

View File

@@ -32,6 +32,10 @@ _SD_BLOCK_RE = re.compile(r'\[decnet@55555\s+(.*?)\]', re.DOTALL)
_PARAM_RE = re.compile(r'(\w+)="((?:[^"\\]|\\.)*)"') _PARAM_RE = re.compile(r'(\w+)="((?:[^"\\]|\\.)*)"')
_IP_FIELDS = ("src_ip", "src", "client_ip", "remote_ip", "ip") _IP_FIELDS = ("src_ip", "src", "client_ip", "remote_ip", "ip")
# bash PROMPT_COMMAND logger output: "CMD uid=0 pwd=/root cmd=ls -lah"
_BASH_CMD_RE = re.compile(r"CMD\s+uid=(\S+)\s+pwd=(\S+)\s+cmd=(.*)")
def parse_rfc5424(line: str) -> Optional[dict[str, Any]]: def parse_rfc5424(line: str) -> Optional[dict[str, Any]]:
""" """
@@ -70,6 +74,16 @@ def parse_rfc5424(line: str) -> Optional[dict[str, Any]]:
except ValueError: except ValueError:
ts_formatted = ts_raw ts_formatted = ts_raw
# Normalize bash CMD lines from SSH honeypot PROMPT_COMMAND logger
if service == "bash" and msg:
cmd_match = _BASH_CMD_RE.match(msg)
if cmd_match:
service = "ssh"
event_type = "command"
fields["uid"] = cmd_match.group(1)
fields["pwd"] = cmd_match.group(2)
fields["command"] = cmd_match.group(3)
return { return {
"timestamp": ts_formatted, "timestamp": ts_formatted,
"decky": decky, "decky": decky,

View File

@@ -40,6 +40,9 @@ _PARAM_RE = re.compile(r'(\w+)="((?:[^"\\]|\\.)*)"')
# Field names to probe for attacker IP, in priority order # Field names to probe for attacker IP, in priority order
_IP_FIELDS = ("src_ip", "src", "client_ip", "remote_ip", "ip") _IP_FIELDS = ("src_ip", "src", "client_ip", "remote_ip", "ip")
# bash PROMPT_COMMAND logger output: "CMD uid=0 pwd=/root cmd=ls -lah"
_BASH_CMD_RE = re.compile(r"CMD\s+uid=(\S+)\s+pwd=(\S+)\s+cmd=(.*)")
@dataclass @dataclass
class LogEvent: class LogEvent:
@@ -99,6 +102,19 @@ def parse_line(line: str) -> LogEvent | None:
return None return None
fields = _parse_sd_params(sd_rest) fields = _parse_sd_params(sd_rest)
# Normalize bash CMD lines from SSH honeypot PROMPT_COMMAND logger
if service == "bash":
# Free-text MSG follows the SD element (which is "-" for these lines)
msg = sd_rest.lstrip("- ").strip()
cmd_match = _BASH_CMD_RE.match(msg)
if cmd_match:
service = "ssh"
event_type = "command"
fields["uid"] = cmd_match.group(1)
fields["pwd"] = cmd_match.group(2)
fields["command"] = cmd_match.group(3)
attacker_ip = _extract_attacker_ip(fields) attacker_ip = _extract_attacker_ip(fields)
return LogEvent( return LogEvent(

View File

@@ -131,6 +131,32 @@ class TestParseRfc5424:
assert result["msg"] == "login attempt" assert result["msg"] == "login attempt"
def test_bash_cmd_normalized_to_ssh_command(self):
line = '<14>1 2026-04-14T05:48:12.628417+00:00 SRV-BRAVO-13 bash - - - CMD uid=0 pwd=/root cmd=ls /var/www/html'
result = parse_rfc5424(line)
assert result is not None
assert result["service"] == "ssh"
assert result["event_type"] == "command"
assert result["fields"]["command"] == "ls /var/www/html"
assert result["fields"]["uid"] == "0"
assert result["fields"]["pwd"] == "/root"
def test_bash_cmd_simple_command(self):
line = '<14>1 2026-04-14T05:48:13.332072+00:00 SRV-BRAVO-13 bash - - - CMD uid=0 pwd=/root cmd=ls'
result = parse_rfc5424(line)
assert result is not None
assert result["service"] == "ssh"
assert result["event_type"] == "command"
assert result["fields"]["command"] == "ls"
def test_bash_non_cmd_not_normalized(self):
line = '<14>1 2026-04-14T05:48:12.628417+00:00 SRV-BRAVO-13 bash - - - some other bash message'
result = parse_rfc5424(line)
assert result is not None
assert result["service"] == "bash"
assert result["event_type"] == "-"
class TestIsServiceContainer: class TestIsServiceContainer:
def test_known_container_returns_true(self): def test_known_container_returns_true(self):
with patch("decnet.collector.worker._load_service_container_names", return_value=_KNOWN_NAMES): with patch("decnet.collector.worker._load_service_container_names", return_value=_KNOWN_NAMES):

View File

@@ -155,6 +155,39 @@ class TestParserAttackerIP:
assert parse_line(line) is None assert parse_line(line) is None
class TestParserBashNormalization:
def test_bash_cmd_normalized_to_ssh_command(self):
line = '<14>1 2026-04-14T05:48:12.628417+00:00 SRV-BRAVO-13 bash - - - CMD uid=0 pwd=/root cmd=ls /var/www/html'
event = parse_line(line)
assert event is not None
assert event.service == "ssh"
assert event.event_type == "command"
assert event.fields["command"] == "ls /var/www/html"
assert event.fields["uid"] == "0"
assert event.fields["pwd"] == "/root"
def test_bash_cmd_simple(self):
line = '<14>1 2026-04-14T05:48:13.332072+00:00 SRV-BRAVO-13 bash - - - CMD uid=0 pwd=/root cmd=ls'
event = parse_line(line)
assert event is not None
assert event.service == "ssh"
assert event.fields["command"] == "ls"
def test_bash_non_cmd_stays_as_bash(self):
line = '<14>1 2026-04-14T05:48:12.628417+00:00 SRV-BRAVO-13 bash - - - some other bash message'
event = parse_line(line)
assert event is not None
assert event.service == "bash"
assert event.event_type == "-"
def test_bash_cmd_with_complex_command(self):
line = '<14>1 2026-04-14T05:48:32.006502+00:00 SRV-BRAVO-13 bash - - - CMD uid=0 pwd=/root cmd=cat /etc/passwd | grep root'
event = parse_line(line)
assert event is not None
assert event.service == "ssh"
assert event.fields["command"] == "cat /etc/passwd | grep root"
# --------------------------------------------------------------------------- # ---------------------------------------------------------------------------
# graph.py — AttackerTraversal # graph.py — AttackerTraversal
# --------------------------------------------------------------------------- # ---------------------------------------------------------------------------