EVT files are Windows Event Log files written by older Windows
operating systems (2000, XP, 2003). They are used as binary log
files by several major Windows subsystems and
applications. Typically, several of them can be found in
%WINDIR%\system32\config directory:
AppEvent.evtSysEvent.evtSecEvent.evtAlternatively, one can export any system event log as distinct .evt file using relevant option in Event Viewer application.
A Windows application can submit an entry into these logs using ReportEventA function of Windows API.
Internally, EVT files consist of a fixed-size header and event records. There are several usage scenarios (non-wrapping vs wrapping log files) which result in slightly different organization of records.
This page hosts a formal specification of Windows Event Log (EVT) using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.
The Python runtime library can be installed from PyPI:
python3 -m pip install kaitaistructParse a local file and get structure in memory:
data = WindowsEvtLog.from_file("path/to/local/file.evt")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = WindowsEvtLog(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.header # => get header
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
# type: ignore
import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
from enum import IntEnum
if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 11):
raise Exception("Incompatible Kaitai Struct Python API: 0.11 or later is required, but you have %s" % (kaitaistruct.__version__))
class WindowsEvtLog(KaitaiStruct):
"""EVT files are Windows Event Log files written by older Windows
operating systems (2000, XP, 2003). They are used as binary log
files by several major Windows subsystems and
applications. Typically, several of them can be found in
`%WINDIR%\system32\config` directory:
* Application = `AppEvent.evt`
* System = `SysEvent.evt`
* Security = `SecEvent.evt`
Alternatively, one can export any system event log as distinct .evt
file using relevant option in Event Viewer application.
A Windows application can submit an entry into these logs using
[ReportEventA](https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-reporteventa)
function of Windows API.
Internally, EVT files consist of a fixed-size header and event
records. There are several usage scenarios (non-wrapping vs wrapping
log files) which result in slightly different organization of
records.
.. seealso::
Source - https://learn.microsoft.com/en-us/windows/win32/eventlog/event-log-file-format
"""
def __init__(self, _io, _parent=None, _root=None):
super(WindowsEvtLog, self).__init__(_io)
self._parent = _parent
self._root = _root or self
self._read()
def _read(self):
self.header = WindowsEvtLog.Header(self._io, self, self._root)
self.records = []
i = 0
while not self._io.is_eof():
self.records.append(WindowsEvtLog.Record(self._io, self, self._root))
i += 1
def _fetch_instances(self):
pass
self.header._fetch_instances()
for i in range(len(self.records)):
pass
self.records[i]._fetch_instances()
class CursorRecordBody(KaitaiStruct):
"""
.. seealso::
Source - https://forensics.wiki/windows_event_log_(evt)/#cursor-record
"""
def __init__(self, _io, _parent=None, _root=None):
super(WindowsEvtLog.CursorRecordBody, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.magic = self._io.read_bytes(12)
if not self.magic == b"\x22\x22\x22\x22\x33\x33\x33\x33\x44\x44\x44\x44":
raise kaitaistruct.ValidationNotEqualError(b"\x22\x22\x22\x22\x33\x33\x33\x33\x44\x44\x44\x44", self.magic, self._io, u"/types/cursor_record_body/seq/0")
self.ofs_first_record = self._io.read_u4le()
self.ofs_next_record = self._io.read_u4le()
self.idx_next_record = self._io.read_u4le()
self.idx_first_record = self._io.read_u4le()
def _fetch_instances(self):
pass
class Header(KaitaiStruct):
"""
.. seealso::
Source - https://learn.microsoft.com/en-us/previous-versions/windows/desktop/legacy/bb309024(v=vs.85)
"""
def __init__(self, _io, _parent=None, _root=None):
super(WindowsEvtLog.Header, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.len_header = self._io.read_u4le()
self.magic = self._io.read_bytes(4)
if not self.magic == b"\x4C\x66\x4C\x65":
raise kaitaistruct.ValidationNotEqualError(b"\x4C\x66\x4C\x65", self.magic, self._io, u"/types/header/seq/1")
self.version_major = self._io.read_u4le()
self.version_minor = self._io.read_u4le()
self.ofs_start = self._io.read_u4le()
self.ofs_end = self._io.read_u4le()
self.cur_rec_idx = self._io.read_u4le()
self.oldest_rec_idx = self._io.read_u4le()
self.len_file_max = self._io.read_u4le()
self.flags = WindowsEvtLog.Header.Flags(self._io, self, self._root)
self.retention = self._io.read_u4le()
self.len_header_2 = self._io.read_u4le()
def _fetch_instances(self):
pass
self.flags._fetch_instances()
class Flags(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
super(WindowsEvtLog.Header.Flags, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.reserved = self._io.read_bits_int_be(28)
self.archive = self._io.read_bits_int_be(1) != 0
self.log_full = self._io.read_bits_int_be(1) != 0
self.wrap = self._io.read_bits_int_be(1) != 0
self.dirty = self._io.read_bits_int_be(1) != 0
def _fetch_instances(self):
pass
class Record(KaitaiStruct):
"""
.. seealso::
Source - https://learn.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-eventlogrecord
"""
def __init__(self, _io, _parent=None, _root=None):
super(WindowsEvtLog.Record, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.len_record = self._io.read_u4le()
self.type = self._io.read_u4le()
_on = self.type
if _on == 1699505740:
pass
self._raw_body = self._io.read_bytes(self.len_record - 12)
_io__raw_body = KaitaiStream(BytesIO(self._raw_body))
self.body = WindowsEvtLog.RecordBody(_io__raw_body, self, self._root)
elif _on == 286331153:
pass
self._raw_body = self._io.read_bytes(self.len_record - 12)
_io__raw_body = KaitaiStream(BytesIO(self._raw_body))
self.body = WindowsEvtLog.CursorRecordBody(_io__raw_body, self, self._root)
else:
pass
self.body = self._io.read_bytes(self.len_record - 12)
self.len_record2 = self._io.read_u4le()
def _fetch_instances(self):
pass
_on = self.type
if _on == 1699505740:
pass
self.body._fetch_instances()
elif _on == 286331153:
pass
self.body._fetch_instances()
else:
pass
class RecordBody(KaitaiStruct):
"""
.. seealso::
Source - https://learn.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-eventlogrecord
"""
class EventTypes(IntEnum):
error = 1
audit_failure = 2
audit_success = 3
info = 4
warning = 5
def __init__(self, _io, _parent=None, _root=None):
super(WindowsEvtLog.RecordBody, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.idx = self._io.read_u4le()
self.time_generated = self._io.read_u4le()
self.time_written = self._io.read_u4le()
self.event_id = self._io.read_u4le()
self.event_type = KaitaiStream.resolve_enum(WindowsEvtLog.RecordBody.EventTypes, self._io.read_u2le())
self.num_strings = self._io.read_u2le()
self.event_category = self._io.read_u2le()
self.reserved = self._io.read_bytes(6)
self.ofs_strings = self._io.read_u4le()
self.len_user_sid = self._io.read_u4le()
self.ofs_user_sid = self._io.read_u4le()
self.len_data = self._io.read_u4le()
self.ofs_data = self._io.read_u4le()
def _fetch_instances(self):
pass
_ = self.data
if hasattr(self, '_m_data'):
pass
_ = self.user_sid
if hasattr(self, '_m_user_sid'):
pass
@property
def data(self):
if hasattr(self, '_m_data'):
return self._m_data
_pos = self._io.pos()
self._io.seek(self.ofs_data - 8)
self._m_data = self._io.read_bytes(self.len_data)
self._io.seek(_pos)
return getattr(self, '_m_data', None)
@property
def user_sid(self):
if hasattr(self, '_m_user_sid'):
return self._m_user_sid
_pos = self._io.pos()
self._io.seek(self.ofs_user_sid - 8)
self._m_user_sid = self._io.read_bytes(self.len_user_sid)
self._io.seek(_pos)
return getattr(self, '_m_user_sid', None)