dissect.cobaltstrike.beacon

This module is responsible for extracting and parsing configuration from Cobalt Strike beacon payloads.

Module Contents

Classes

BeaconConfig

A BeaconConfig object represents a single Beacon configuration

Functions

find_beacon_config_bytes(fh: BinaryIO, xorkey: bytes) → Iterator[bytes]

Find and yield (possible) Cobalt Strike configuration bytes from file fh using xorkey (eg: b"x69").

iter_beacon_config_blocks(fobj: BinaryIO, xor_keys=None, xordecode=True, all_xor_keys=False) → Iterator[Tuple[bytes, dict]]

Yield tuple with found Beacon config_block_bytes from file fobj and extra_info dict

make_byte_list(exclude: List[bytes] = None) → List[bytes]

Return all single-byte bytes as an ordered list, excluding exclude bytes.

iter_settings(fobj: Union[bytes, BinaryIO]) → Iterator[Setting]

Returns an iterator yielding Setting objects by reading data from fobj

grouper(iterable, n, fillvalue=None)

Collect data into fixed-length chunks or blocks

parse_recover_binary(program: bytes) → List[Tuple[str, Union[int, bool]]]

Parse SETTING_C2_RECOVER (.http-get.server.output) data

parse_transform_binary(program: bytes, build: str = 'metadata') → List[Tuple[str, Union[str, bytes, bool]]]

Parse SETTING_C2_{REQUEST,POSTREQ} (http-{get,post}.client) data

parse_execute_list(data: bytes) → List[str]

Parse SETTING_PROCINJ_EXECUTE (.process-inject.execute) data

parse_process_injection_transform_steps(data: bytes) → list

Parse SETTING_PROCINJ_TRANSFORM_X{86,64} (process-inject.transform-x{86,64}) data

parse_gargle(data: bytes) → list

Parse SETTING_GARGLE_SECTIONS (.stage.{sleep_mask,obfuscate,userwx}) data

parse_pivot_frame(data: bytes) → bytes

Parse SETTING_{TCP,SMB}_FRAME_HEADER (.{tcp,smb}_frame_header) data

sha256sum_pubkey(der_data: bytes) → str

Return the SHA-256 digest of der_data

null_terminated_bytes(data: bytes) → bytes

Return null terminated data as bytes.

null_terminated_str(data: bytes) → str

Return null terminated data as string. Non ascii characters are ignored.

build_parser()

main()

Entrypoint for beacon-dump.

Attributes

logger

CS_DEF

cs_struct

TransformStep

BeaconSetting

DeprecatedBeaconSetting

SettingsType

Setting

BeaconProtocol

CryptoScheme

ProxyServer

InjectAllocator

InjectExecutor

DEFAULT_XOR_KEYS

Default XOR keys used by Cobalt Strike for obfuscating Beacon config bytes

SETTING_TO_PRETTYFUNC

BeaconSetting enum to pretty function mapping
dissect.cobaltstrike.beacon.logger[source]
dissect.cobaltstrike.beacon.CS_DEF = Multiline-String[source]
Show Value
  1enum BeaconSetting: uint16 {
  2    SETTING_PROTOCOL = 1,
  3    SETTING_PORT = 2,
  4    SETTING_SLEEPTIME = 3,
  5    SETTING_MAXGET = 4,
  6    SETTING_JITTER = 5,
  7    SETTING_MAXDNS = 6,
  8    SETTING_PUBKEY = 7,
  9    SETTING_DOMAINS = 8,
 10    SETTING_USERAGENT = 9,
 11    SETTING_SUBMITURI = 10,
 12    SETTING_C2_RECOVER = 11,
 13    SETTING_C2_REQUEST = 12,
 14    SETTING_C2_POSTREQ = 13,
 15    SETTING_SPAWNTO = 14,       // releasenotes.txt
 16
 17    // CobaltStrike version >= 3.4 (27 Jul, 2016)
 18    SETTING_PIPENAME = 15,
 19    SETTING_KILLDATE_YEAR = 16,
 20    SETTING_KILLDATE_MONTH = 17,
 21    SETTING_KILLDATE_DAY = 18,
 22    SETTING_DNS_IDLE = 19,
 23    SETTING_DNS_SLEEP = 20,
 24
 25    // CobaltStrike version >= 3.5 (22 Sept, 2016)
 26    SETTING_SSH_HOST = 21,
 27    SETTING_SSH_PORT = 22,
 28    SETTING_SSH_USERNAME = 23,
 29    SETTING_SSH_PASSWORD = 24,
 30    SETTING_SSH_KEY = 25,
 31    SETTING_C2_VERB_GET = 26,
 32    SETTING_C2_VERB_POST = 27,
 33    SETTING_C2_CHUNK_POST = 28,
 34    SETTING_SPAWNTO_X86 = 29,
 35    SETTING_SPAWNTO_X64 = 30,
 36
 37    // CobaltStrike version >= 3.6 (8 Dec, 2016)
 38    SETTING_CRYPTO_SCHEME = 31,
 39
 40    // CobaltStrike version >= 3.7 (15 Mar, 2016)
 41    SETTING_PROXY_CONFIG = 32,
 42    SETTING_PROXY_USER = 33,
 43    SETTING_PROXY_PASSWORD = 34,
 44    SETTING_PROXY_BEHAVIOR = 35,
 45
 46    // CobaltStrike version >= 3.8 (23 May 2017)
 47    // DEPRECATED_SETTING_INJECT_OPTIONS = 36,
 48
 49    // Renamed from DEPRECATED_SETTING_INJECT_OPTIONS in CobaltStrike 4.5
 50    SETTING_WATERMARKHASH = 36,
 51
 52    // CobaltStrike version >= 3.9  (Sept 26, 2017)
 53    SETTING_WATERMARK = 37,
 54
 55    // CobaltStrike version >= 3.11 (April 9, 2018)
 56    SETTING_CLEANUP = 38,
 57
 58    // CobaltStrike version >= 3.11 (May 24, 2018)
 59    SETTING_CFG_CAUTION = 39,
 60
 61    // CobaltStrike version >= 3.12 (Sept 6, 2018)
 62    SETTING_KILLDATE = 40,
 63    SETTING_GARGLE_NOOK = 41,       // https://www.youtube.com/watch?v=nLTgWdXrx3U
 64    SETTING_GARGLE_SECTIONS = 42,
 65    SETTING_PROCINJ_PERMS_I = 43,
 66    SETTING_PROCINJ_PERMS = 44,
 67    SETTING_PROCINJ_MINALLOC = 45,
 68    SETTING_PROCINJ_TRANSFORM_X86 = 46,
 69    SETTING_PROCINJ_TRANSFORM_X64 = 47,
 70    SETTING_PROCINJ_ALLOWED = 48,
 71
 72    // CobaltStrike version >= 3.13 (Jan 2, 2019)
 73    SETTING_BINDHOST = 49,
 74
 75    // CobaltStrike version >= 3.14 (May 4, 2019)
 76    SETTING_HTTP_NO_COOKIES = 50,
 77    SETTING_PROCINJ_EXECUTE = 51,
 78    SETTING_PROCINJ_ALLOCATOR = 52,
 79    SETTING_PROCINJ_STUB = 53,      // .self = MD5(cobaltstrike.jar)
 80
 81    // CobaltStrike version >= 4.0 (Dec 5, 2019)
 82    SETTING_HOST_HEADER = 54,
 83    SETTING_EXIT_FUNK = 55,
 84
 85    // CobaltStrike version >= 4.1 (June 25, 2020)
 86    SETTING_SSH_BANNER = 56,
 87    SETTING_SMB_FRAME_HEADER = 57,
 88    SETTING_TCP_FRAME_HEADER = 58,
 89
 90    // CobaltStrike version >= 4.2 (Nov 6, 2020)
 91    SETTING_HEADERS_REMOVE = 59,
 92
 93    // CobaltStrike version >= 4.3 (Mar 3, 2021)
 94    SETTING_DNS_BEACON_BEACON = 60,
 95    SETTING_DNS_BEACON_GET_A = 61,
 96    SETTING_DNS_BEACON_GET_AAAA = 62,
 97    SETTING_DNS_BEACON_GET_TXT = 63,
 98    SETTING_DNS_BEACON_PUT_METADATA = 64,
 99    SETTING_DNS_BEACON_PUT_OUTPUT = 65,
100    SETTING_DNSRESOLVER = 66,
101    SETTING_DOMAIN_STRATEGY = 67,
102    SETTING_DOMAIN_STRATEGY_SECONDS = 68,
103    SETTING_DOMAIN_STRATEGY_FAIL_X = 69,
104    SETTING_DOMAIN_STRATEGY_FAIL_SECONDS = 70,
105
106    // CobaltStrike version >= 4.5 (Dec 14, 2021)
107    SETTING_MAX_RETRY_STRATEGY_ATTEMPTS = 71,
108    SETTING_MAX_RETRY_STRATEGY_INCREASE = 72,
109    SETTING_MAX_RETRY_STRATEGY_DURATION = 73,
110};
111
112enum DeprecatedBeaconSetting: uint16 {
113    SETTING_INJECT_OPTIONS = 36,
114};
115
116enum TransformStep: uint32 {
117    APPEND = 1,
118    PREPEND = 2,
119    BASE64 = 3,
120    PRINT = 4,
121    PARAMETER = 5,
122    HEADER = 6,
123    BUILD = 7,
124    NETBIOS = 8,
125    _PARAMETER = 9,
126    _HEADER = 10,
127    NETBIOSU = 11,
128    URI_APPEND = 12,
129    BASE64URL = 13,
130    STRREP = 14,
131    MASK = 15,
132    // CobaltStrike version >= 4.0 (Dec 5, 2019)
133    _HOSTHEADER = 16,
134};
135
136enum SettingsType: uint16 {
137    TYPE_NONE = 0,
138    TYPE_SHORT = 1,
139    TYPE_INT = 2,
140    TYPE_PTR = 3,
141};
142
143struct Setting {
144    BeaconSetting index;    // uint16
145    SettingsType type;      // uint16
146    uint16 length;          // uint16
147    char value[length];
148};
149
150flag BeaconProtocol {
151    http = 0,
152    dns = 1,
153    smb = 2,
154    tcp = 4,
155    https = 8,
156    bind = 16
157};
158
159flag ProxyServer {
160    MANUAL = 0,
161    DIRECT = 1,
162    PRECONFIG = 2,
163    MANUAL_CREDS = 4
164};
165
166enum CryptoScheme: uint16 {
167    CRYPTO_LICENSED_PRODUCT = 0,
168    CRYPTO_TRIAL_PRODUCT = 1
169};
170
171enum InjectAllocator: uint8 {
172    VirtualAllocEx = 0,
173    NtMapViewOfSection = 1,
174};
175
176enum InjectExecutor: uint8 {
177    CreateThread = 1,
178    SetThreadContext = 2,
179    CreateRemoteThread = 3,
180    RtlCreateUserThread = 4,
181    NtQueueApcThread = 5,
182    CreateThread_ = 6,
183    CreateRemoteThread_ = 7,
184    NtQueueApcThread_s = 8
185};
dissect.cobaltstrike.beacon.cs_struct[source]
dissect.cobaltstrike.beacon.TransformStep[source]
dissect.cobaltstrike.beacon.BeaconSetting[source]
dissect.cobaltstrike.beacon.DeprecatedBeaconSetting[source]
dissect.cobaltstrike.beacon.SettingsType[source]
dissect.cobaltstrike.beacon.Setting[source]
dissect.cobaltstrike.beacon.BeaconProtocol[source]
dissect.cobaltstrike.beacon.CryptoScheme[source]
dissect.cobaltstrike.beacon.ProxyServer[source]
dissect.cobaltstrike.beacon.InjectAllocator[source]
dissect.cobaltstrike.beacon.InjectExecutor[source]
dissect.cobaltstrike.beacon.DEFAULT_XOR_KEYS :List[bytes] = [b'i', b'.', b'\x00'][source]

Default XOR keys used by Cobalt Strike for obfuscating Beacon config bytes

dissect.cobaltstrike.beacon.find_beacon_config_bytes(fh: BinaryIO, xorkey: bytes) → Iterator[bytes][source]

Find and yield (possible) Cobalt Strike configuration bytes from file fh using xorkey (eg: b”x69”).

This is done by scraping the file fh for XOR encoded configuration blocks. A beacon configuration block always (unless modified) starts with:

Setting(index=SETTING_PROTOCOL, type=TYPE_SHORT, length=0x2)

# which translates to the following bytes
b"\x00\x01\x00\x01\x00\x02\x00"

These bytes are used in conjuction with the XOR key for finding the (potential) start of a configuration block.

Parameters

  • fh – file object

  • xorkey – XOR key (as bytes)

Yields

Beacon configuration bytes (4096 bytes), in deobfuscated (un-XOR’d) form.

dissect.cobaltstrike.beacon.iter_beacon_config_blocks(fobj: BinaryIO, xor_keys=None, xordecode=True, all_xor_keys=False) → Iterator[Tuple[bytes, dict]][source]

Yield tuple with found Beacon config_block_bytes from file fobj and extra_info dict

It always start seeking from the beginning of fobj. Side effects: file handle position due to seeking

The extra_info dictionary holds some metadata such as if the fobj was xorencoded and which xorkey was used.

Parameters

  • xor_keys – list XOR keys (as bytes), defaults to: DEFAULT_XOR_KEYS if not specified.

  • xordecode – If True it will also try to XorDecode the file object.

  • all_xor_keys – Try ALL single-byte XOR keys if no beacon config is found using the default keys.

Yields

Tuple as (config_block_bytes, extra_info_dict) – extra_info dict contains: {"xorkey": bytes, "xorencoded": bool}

dissect.cobaltstrike.beacon.make_byte_list(exclude: List[bytes] = None) → List[bytes][source]

Return all single-byte bytes as an ordered list, excluding exclude bytes.

dissect.cobaltstrike.beacon.iter_settings(fobj: Union[bytes, BinaryIO]) → Iterator[Setting][source]

Returns an iterator yielding Setting objects by reading data from fobj

The file position will be at the end of the Beacon config after parsing is done. This can be used to determine the exact size of the Beacon configuration block.

Some edge cases are also handled:

  • User-Agent string that exceeds the Setting length.

  • Deprecated setting SETTING_INJECT_OPTIONS

Parameters

fobj – bytes or file-like object with Beacon configuration data

Yields

Setting objects

dissect.cobaltstrike.beacon.grouper(iterable, n, fillvalue=None)[source]

Collect data into fixed-length chunks or blocks

dissect.cobaltstrike.beacon.parse_recover_binary(program: bytes) → List[Tuple[str, Union[int, bool]]][source]

Parse SETTING_C2_RECOVER (.http-get.server.output) data

dissect.cobaltstrike.beacon.parse_transform_binary(program: bytes, build: str = 'metadata') → List[Tuple[str, Union[str, bytes, bool]]][source]

Parse SETTING_C2_{REQUEST,POSTREQ} (http-{get,post}.client) data

dissect.cobaltstrike.beacon.parse_execute_list(data: bytes) → List[str][source]

Parse SETTING_PROCINJ_EXECUTE (.process-inject.execute) data

dissect.cobaltstrike.beacon.parse_process_injection_transform_steps(data: bytes) → list[source]

Parse SETTING_PROCINJ_TRANSFORM_X{86,64} (process-inject.transform-x{86,64}) data

dissect.cobaltstrike.beacon.parse_gargle(data: bytes) → list[source]

Parse SETTING_GARGLE_SECTIONS (.stage.{sleep_mask,obfuscate,userwx}) data

dissect.cobaltstrike.beacon.parse_pivot_frame(data: bytes) → bytes[source]

Parse SETTING_{TCP,SMB}_FRAME_HEADER (.{tcp,smb}_frame_header) data

dissect.cobaltstrike.beacon.sha256sum_pubkey(der_data: bytes) → str[source]

Return the SHA-256 digest of der_data

dissect.cobaltstrike.beacon.null_terminated_bytes(data: bytes) → bytes[source]

Return null terminated data as bytes.

>>> null_terminated_bytes(b"Hello World\x00\x00Foobar\x00\x00")
b'Hello World'
>>> null_terminated_bytes(b"foo\xffbar\x00\x00\x00baz\x00")
b'foo\xffbar'
dissect.cobaltstrike.beacon.null_terminated_str(data: bytes) → str[source]

Return null terminated data as string. Non ascii characters are ignored.

>>> null_terminated_str(b"Hello World\x00\x00foo bar\x00\x00")
'Hello World'
>>> null_terminated_str(b"Goodbye\xffPlanet\x00\x00")
'GoodbyePlanet'
dissect.cobaltstrike.beacon.SETTING_TO_PRETTYFUNC :Dict[BeaconSetting, Callable][source]

BeaconSetting enum to pretty function mapping

class dissect.cobaltstrike.beacon.BeaconConfig(config_block: bytes)[source]

A BeaconConfig object represents a single Beacon configuration

It holds configuration data, parsed settings and other metadata of a Cobalt Strike Beacon and provides useful methods and properties for accessing the Beacon settings. It does not contain the Beacon payload data itself.

It can be directly instantiated using configuration data. Otherwise, use the following constructors:

The from_ constructors automatically tries to extract the configuration data (first candidate only) and also handles xorencoded payloads and XOR decoding of obfuscated configuration blocks that is common with Cobalt Strike.

config_block :bytes[source]

Raw beacon configuration block bytes

settings_tuple[source]

Tuple containing the Setting objects parsed from config_block

xorkey :Optional[bytes][source]

XOR key that was used to obfuscate the configuration block, None if unknown.

xorencoded :bool = False[source]

True if the beacon was xorencoded, otherwise False

pe_export_stamp :Optional[int][source]

PE export timestamp, None if unknown.

pe_compile_stamp :Optional[int][source]

PE compile timestamp, None if unknown.

architecture :Optional[str][source]

PE architecture, "x86" or "x64" and None if unknown.

classmethod from_file(cls, fobj: BinaryIO, xor_keys: List[bytes] = None, all_xor_keys: bool = False) → BeaconConfig[source]

Create a BeaconConfig from file object, or raises ValueError if no beacon config is found.

Parameters

  • fobj – file-like object

  • xor_keys – override the default XOR keys (as bytes) when specified. Default None.

  • all_xor_keys – if True, it will try ALL single-byte XOR keys if the defaults don’t work

Returns

BeaconConfig

Raises

ValueError – If no valid beacon configuration was found

classmethod from_path(cls, path: Union[str, os.PathLike], xor_keys: List[bytes] = None, all_xor_keys: bool = False) → BeaconConfig[source]

Create a BeaconConfig from path, or raises ValueError if no beacon config is found.

Parameters

  • path – path to file on disk

  • xor_keys – override the default XOR keys (as bytes) when specified. Default None.

  • all_xor_keys – if True it will try ALL single-byte XOR keys if the defaults don’t work

Returns

BeaconConfig

Raises

ValueError – If no valid beacon configuration was found

classmethod from_bytes(cls, data: bytes, xor_keys: List[bytes] = None, all_xor_keys: bool = False) → BeaconConfig[source]

Create a BeaconConfig from bytes, or raises ValueError if no beacon config is found.

Parameters

  • data – configuration bytes

  • xor_keys – override the default XOR keys when specified. Default None.

  • all_xor_keys – if True it will try ALL single-byte XOR keys if the defaults don’t work

Returns

BeaconConfig

Raises

ValueError – If no valid beacon configuration was found

__repr__(self) → str[source]

Return repr(self).

property setting_enums(self) → list[source]

List of BeaconSetting enum values in the order of appearance within the Beacon configuration. Example value:

[1, 2, 3, 4, 5, 7, ..., 45, 46, 47, 53, 51, 52]
property max_setting_enum(self) → int[source]

The maximum BeaconSetting enum value present in the Beacon configuration.

settings_map(self, index_type='enum', pretty=False, parse=True) → types.MappingProxyType[source]

Return a read-only settings mapping indexed by given index_type.

Parameters

  • index_type –

    index type of the dictionary, can be one of:

    • name: indexed by BeaconSetting name (str)

    • const: indexed by BeaconSetting constant (int)

    • enum: indexed by BeaconSetting enum (enum object).

  • pretty – if True, apply pretty functions on the values.

  • parse – if True, the raw bytes of TYPE_SHORT and TYPE_INT values are converted to int.

Returns

OrderedDict

property raw_settings(self) → Mapping[str, Any][source]

Read-only Beacon settings mapping with raw values, indexed by BeaconSetting name.

The raw bytes of TYPE_SHORT and TYPE_INT values are converted to int. Example value:

mappingproxy({
    'SETTING_PROTOCOL': 8,
    'SETTING_PORT': 443,
    'SETTING_SLEEPTIME': 60000,
    ...
    'SETTING_C2_VERB_POST': b'POST\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
    'SETTING_PROCINJ_STUB': b'\x0c\xe2\xf5TD\xe4y5\x16\xb5\xaf\xe9g\xbe\x92U',
})
property raw_settings_by_index(self) → Mapping[int, Any][source]

Read-only Beacon settings mapping with raw values, indexed by BeaconSetting constant.

The raw bytes of TYPE_SHORT and TYPE_INT values are converted to int. Example value:

mappingproxy({
    1: 8,
    2: 443,
    3: 60000,
    ...
    27: b'POST\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
    53: b'\x0c\xe2\xf5TD\xe4y5\x16\xb5\xaf\xe9g\xbe\x92U',
})
property settings(self) → Mapping[str, Any][source]

Read-only Beacon settings mapping with human readable values, indexed by BeaconSetting name. Example value:

mappingproxy({
    'SETTING_PROTOCOL': 8,
    'SETTING_PORT': 443,
    'SETTING_SLEEPTIME': 60000,
    ...
    'SETTING_C2_VERB_POST': 'POST',
    'SETTING_PROCINJ_STUB': '0ce2f55444e4793516b5afe967be9255',
})
property settings_by_index(self) → Mapping[int, Any][source]

Read-only Beacon settings mapping with human readable values, indexed by BeaconSetting constant. Example value:

mappingproxy({
    1: 8,
    2: 443,
    3: 60000,
    ...
    27: 'POST',
    53: '0ce2f55444e4793516b5afe967be9255',
})
property domain_uri_pairs(self) → List[Tuple[str, str]][source]

List of configured (domain, uri) pairs in the Beacon. Example value:

[
    ('c1.example.com', '/__utm.gif'),
    ('c2.example.com', '/en_US/all.js'),
]
property uris(self) → List[str][source]

List of configured Beacon URIs. Example value:

['/__utm.gif', '/en_US/all.js']
property domains(self) → List[str][source]

List of configured Beacon domains. Example value:

['c1.example.com', 'c2.example.com']
property killdate(self) → Optional[str][source]

Normalized kill date as YYYY-mm-dd string or None if not defined in Beacon.

Note

The reason why the return type is a str instead of a datetime.date object is that the configured killdate in the Beacon can be arbitrary. e.g. 9999-99-99

property protocol(self) → Optional[str][source]

The protocol the Beacon uses for communication, e.g. "http", "dns". None if unknown.

property watermark(self) → Optional[int][source]

Beacon watermark (also known as customer or authorization id).

property is_trial(self) → bool[source]

True if Beacon is a trial version (CRYPTO_TRIAL_PRODUCT). Otherwise, False.

property version(self) → dissect.cobaltstrike.version.BeaconVersion[source]

Deduced version of Cobalt Strike as BeaconVersion object.

The version is deduced from the Beacon’s pe_export_stamp when available, otherwise from max_setting_enum.

dissect.cobaltstrike.beacon.build_parser()[source]
dissect.cobaltstrike.beacon.main()[source]

Entrypoint for beacon-dump.