D(HE)ater is a security tool can perform DoS attack by enforcing the DHE key exchange.

Balasys

Last update: Dec 15, 2022

Related tags

Third-party APIs Wrappers tls ssh denial-of-service overloading diffie-hellman-algorithm dhe diffie-hellman-exchange

Overview

D(HE)ater

D(HE)ater is an attacking tool based on CPU heating in that it forces the ephemeral variant of Diffie-Hellman key exchange (DHE) in given cryptography protocols (e.g. TLS, SSH). It is performed without calculating a cryptographically correct ephemeral key on the client side, but with a significant amount of calculation on the server side. Based on this, D(HE)ater can initiate a denial-of-service (DoS) attack.

Quick start

D(HE)ater can be installed directly via pip from PyPi

pip install dheater
dheat --protocol tls ecc256.badssl.com
dheat --protocol ssh ecc256.badssl.com

or can be used via Docker from Docker Hub

docker pull balasys/dheater
docker run --tty --rm balasys/dheater --protocol tls ecc256.badssl.com
docker run --tty --rm balasys/dheater --protocol ssh ecc256.badssl.com

You can increase load by string extra threads.

dheat --thread-num 4 --protocol tls ecc256.badssl.com
docker run --tty --rm balasys/dheater --thread-num 4 --protocol tls ecc256.badssl.com
docker run --tty --rm balasys/dheater --thread-num 4 --protocol ssh ecc256.badssl.com

Mitigation

Configuration

Diffie-Hellman (DHE) key exchange should be disabled.

TLS

Apache

SSLCipherSuite ...:!kDHE

NGINX

ssl_ciphers ...:!kDHE;

Others

See moz://a SSL Configuration Generator for configuration syntax.

SSH

OpenSSH

KexAlgorithms -diffie-hellman-group1-sha1,diffie-hellman-group1-sha256,diffie-hellman-group14-sha1,diffie-hellman-group14-sha256,diffie-hellman-group15-sha256,diffie-hellman-group15-sha512,diffie-hellman-group16-sha256,diffie-hellman-group16-sha512,diffie-hellman-group17-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha512

Fail2Ban

TLS

Apache

There are no relevant filters.

apache-ssl.conf in fail2ban directory should be copied to the filter.d directory under the fail2ban configuration directory
the followings should be added to the jail.local file in the fail2ban configuration directory

[apache-ssl]

port    = https
logpath = %(apache_error_log)s
maxretry = 1

Postfix

There is a relevant filter, but it is applied only in ddos mode. The followings should be added to jail.local.

[postfix]
mode = ddos

Dovecot

There is a relevant filter, but it is applied only in ddos mode. The followings should be added to jail.local.

[dovecot]
mode = aggressive

or a specific filter can be used without changing the mode of dovecot.

dovecot-ssl.conf in fail2ban directory should be copied to the filter.d directory under the fail2ban configuration directory
the followings should be added to jail.local in tge fail2ban configuration directory

[dovecot-ssl]

port    = pop3,pop3s,imap,imaps,submission,465,sieve
logpath = %(dovecot_log)s
backend = %(dovecot_backend)s
maxretry = 1

SSH

OpenSSH

There is a relevant filter, but it is applied only in ddos mode. The followings should be added to jail.local.

[sshd]
mode = ddos

License

The code is available under the terms of Apache License Version 2.0. A non-comprehensive, but straightforward description and also the full license text can be found at Choose an open source license website.

Comments

not able to use

Hello,

I'm very new to this cybersecurity field Please anyone help me out with this problem. ### Note I have replace website name with ConfidentialWebsite.com

When I use tls protocol I'm getting this error :-

dheat --protocol tls ConfidentialWebsite.com Traceback (most recent call last): File "/usr/local/bin/dheat", line 8, in sys.exit(main()) File "/usr/local/lib/python3.9/dist-packages/dheater/main.py", line 512, in main enforcer = DHEnforcerThreadTLS(args.uri, args.timeout, pre_check_result) File "", line 14, in init File "/usr/local/lib/python3.9/dist-packages/dheater/main.py", line 125, in attrs_post_init self._pre_check() File "/usr/local/lib/python3.9/dist-packages/dheater/main.py", line 390, in _pre_check if is_tls_1_3: NameError: name 'is_tls_1_3' is not defined

When I use ssh protocol I'm getting this error :-

dheat --protocol ssh ConfidentialWebsite.com
Network error oocuerd while checking whether Diffie-Hellman ephemeral (DHE) key exchange is supported by the server; uri="ConfidentialWebsite.com", error="connection to target cannot be established"

bug

opened by souravkr529 5

It does not run from docker image

I have ran the mentioned command: docker run --tty --rm balasys/dheater --protocol ssh ecc256.badssl.com andresulted the following error:

#docker run --tty --rm balasys/dheater --thread-num 4 --protocol ssh ecc256.badssl.com
Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/common/transfer.py", line 139, in _init_connection
    self._socket = socket.create_connection((self.ip, self.port), self.timeout)
  File "/usr/local/lib/python3.9/socket.py", line 844, in create_connection
    raise err
  File "/usr/local/lib/python3.9/socket.py", line 832, in create_connection
    sock.connect(sa)
socket.timeout: timed out
 
The above exception was the direct cause of the following exception:
 
Traceback (most recent call last):
  File "/usr/local/bin/dheat", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.9/site-packages/dheater/__main__.py", line 258, in main
    enforcer = DHEnforcerThreadSSH(args.uri, args.timeout, pre_check_result)
  File "<attrs generated init dheater.__main__.DHEnforcerThreadBase>", line 15, in __init__
  File "/usr/local/lib/python3.9/site-packages/dheater/__main__.py", line 89, in __attrs_post_init__
    self._pre_check()
  File "/usr/local/lib/python3.9/site-packages/dheater/__main__.py", line 117, in _pre_check
    self.pre_check_result = analyzer.analyze(self._get_client())
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/ssh/dhparams.py", line 111, in analyze
    analyzer_result = AnalyzerCiphers().analyze(analyzable)
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/ssh/ciphers.py", line 80, in analyze
    server_messages = analyzable.do_handshake(last_message_type=SshMessageCode.KEXINIT)
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/ssh/client.py", line 111, in do_handshake
    self.init_connection()
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/common/transfer.py", line 251, in init_connection
    self._init_connection()
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/ssh/client.py", line 102, in _init_connection
    self.l4_transfer.init_connection()
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/common/transfer.py", line 73, in init_connection
    self._init_connection()
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/common/transfer.py", line 142, in _init_connection
    six.raise_from(NetworkError(NetworkErrorType.NO_CONNECTION), e)
  File "<string>", line 3, in raise_from
cryptolyzer.common.exception.NetworkError: connection to target cannot be established

opened by V0072 5

Errors trying to connect to target

@c0r0n3r I can provide wireshark if needed in order to understand why the script fails despite having communication.

Output: C:\Users\t>dheat --protocol tls gw.t.local Network error oocuerd while checking whether Diffie-Hellman ephemeral (DHE) key exchange is supported by the server; uri="gw.t.local", error="connection to target cannot be established"

C:\Users\t>dheat --protocol tls gw.t.local Network error oocuerd while checking whether Diffie-Hellman ephemeral (DHE) key exchange is supported by the server; uri="gw.t.local", error="no response received from target"
question

opened by KyferEz 4

Does not work

Either way I run Install it via pip or use it via Docker I get the following error

┌──(kali㉿kali)-[~]
└─$ docker run --tty --rm balasys/dheater --protocol tls domainwhichiownandreachable.com                                                    1 ⨯
Traceback (most recent call last):
  File "/usr/local/bin/dheat", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.9/site-packages/dheater/__main__.py", line 331, in main
    enforcer = DHEnforcerThreadTLS(args.uri, args.timeout, pre_check_result)
  File "<attrs generated init dheater.__main__.DHEnforcerThreadBase>", line 15, in __init__
  File "/usr/local/lib/python3.9/site-packages/dheater/__main__.py", line 100, in __attrs_post_init__
    self._pre_check()
  File "/usr/local/lib/python3.9/site-packages/dheater/__main__.py", line 264, in _pre_check
    server_messages = self._get_client().do_tls_handshake(
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/tls/client.py", line 429, in do_tls_handshake
    return self._do_handshake(
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/tls/client.py", line 409, in _do_handshake
    l7_client.do_handshake(self, hello_message, record_version, last_handshake_message_type)
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/tls/client.py", line 1181, in do_handshake
    self._process_non_handshake_message(record.content_type, message)
  File "/usr/local/lib/python3.9/site-packages/cryptolyzer/tls/client.py", line 1135, in _process_non_handshake_message
    raise TlsAlert(message.description)
cryptolyzer.tls.exception.TlsAlert: TlsAlert(description=<TlsAlertDescription.HANDSHAKE_FAILURE: 40>)

question

opened by rtcms 4

gnuTLS support?

It seems like it does not work against gnuTLS implementations, but the general problem described in the CVE sounds like it should. Any chance to get it modified for gnuTLS as well...
bug

opened by Lockhead 3
Anti-DDoS Mechanism in openssh-8.5p1

Once, I also submitted a ddos question to the openssh community: https://bugzilla.mindrot.org/show_bug.cgi?id=3211

They added the configuration items PerSourceMaxStartups and PerSourceNetBlockSize to openssh-8.5p1. I think that the two parameters can be properly configured to prevent "dheat" from attacking OpenSSH.
documentation

opened by kircherlike 1

DHEater crashes on hardened SSH server

I just tested this against one of my machines. After bringing my cpu load up to ~70% I tried if I could mitigate this in my sshd by enabling the "modern" hardened configuration as recommended by Mozilla: https://infosec.mozilla.org/guidelines/openssh

Effectively I disabled non-ed25519 hostkeys and enabled the following settings:

KexAlgorithms [email protected],ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256

Ciphers [email protected],[email protected],[email protected],aes256-ctr,aes192-ctr,aes128-ctr

MACs [email protected],[email protected],[email protected],hmac-sha2-512,hmac-sha2-256,[email protected]

Once I reloaded my sshd dheater crashes with the following error:

Traceback (most recent call last):
  File "/opt/homebrew/Cellar/[email protected]/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/opt/homebrew/Cellar/[email protected]/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/Users/rsc/dev/dheater/dheater/__main__.py", line 346, in <module>
    main()
  File "/Users/rsc/dev/dheater/dheater/__main__.py", line 259, in main
    enforcer = DHEnforcerThreadSSH(args.uri, args.timeout, pre_check_result)
  File "<attrs generated init __main__.DHEnforcerThreadBase>", line 15, in __init__
  File "/Users/rsc/dev/dheater/dheater/__main__.py", line 93, in __attrs_post_init__
    self.message_bytes = self._prepare_packets()
  File "/Users/rsc/dev/dheater/dheater/__main__.py", line 153, in _prepare_packets
    key_exchange_algorithm_with_greatest_key_size = self._get_algorithm_with_greatest_key_size()
  File "/Users/rsc/dev/dheater/dheater/__main__.py", line 131, in _get_algorithm_with_greatest_key_size
    if self.pre_check_result.key_exchange.kex_algorithms:
AttributeError: 'NoneType' object has no attribute 'kex_algorithms'

command used: python -m dheater --protocol ssh myhost

I haven't bothered looking into this further, but if this disables the required DHE (looks like there's already a check for TLS) this should also be listed as possible mitigation and a message should be shown instead of the exception.

opened by Nothing4You 1

Minimum versions defined for dependencies do not work

On latest master 09f8cc9597fa0df2c652a760fc4fa4d98d5b6549 I'm getting the following exception:

pdm run python -m dheater --protocol ssh myhost

Traceback (most recent call last):
  File "/home/username/.asdf/installs/python/3.10.1/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/home/username/.asdf/installs/python/3.10.1/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File ".../dheater/dheater/__main__.py", line 22, in <module>
    from cryptoparser.tls.ciphersuite import TlsCipherSuite
  File ".../dheater/__pypackages__/3.10/lib/cryptoparser/tls/ciphersuite.py", line 12, in <module>
    from cryptoparser.tls.version import (
  File ".../dheater/__pypackages__/3.10/lib/cryptoparser/tls/version.py", line 24, in <module>
    @attr.s(order=False, eq=False, hash=True)
TypeError: attrs() got an unexpected keyword argument 'order'

this is on Python 3.10.1 on macOS ARM with the following package versions:

asn1crypto==1.4.0
attrs==19.1.0
certifi==2021.10.8
certvalidator==0.11.1
charset-normalizer==2.0.11
cryptolyzer==0.7.2
cryptoparser==0.7.1
idna==3.3
oscrypto==1.2.1
python-dateutil==2.8.2
requests==2.27.1
six==1.16.0
urllib3==1.26.8

bug

opened by Nothing4You 0

software_version must be cryptoparser.ssh.version.SshSoftwareVersionBase

On latest master 09f8cc9597fa0df2c652a760fc4fa4d98d5b6549 I'm getting the following exception:

pdm run python -m dheater --protocol ssh myhost

Traceback (most recent call last):
  File "/home/username/.asdf/installs/python/3.10.1/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/home/username/.asdf/installs/python/3.10.1/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File ".../dheater/dheater/__main__.py", line 565, in <module>
    main()
  File ".../dheater/dheater/__main__.py", line 507, in main
    enforcer = DHEnforcerThreadSSH(args.uri, args.timeout, pre_check_result)
  File "<attrs generated init __main__.DHEnforcerThreadBase>", line 14, in __init__
  File ".../dheater/dheater/__main__.py", line 130, in __attrs_post_init__
    self.message_bytes = self._prepare_packets()
  File ".../dheater/dheater/__main__.py", line 232, in _prepare_packets
    protocol_message = SshProtocolMessage(
  File "<attrs generated init cryptoparser.ssh.subprotocol.SshProtocolMessage>", line 7, in __init__
  File ".../dheater/__pypackages__/3.10/lib/attr/validators.py", line 103, in __call__
    raise TypeError(
TypeError: ("'software_version' must be <class 'cryptoparser.ssh.version.SshSoftwareVersionBase'> (got 'DHEater_0.3.1' that is a <class 'str'>).", Attribute(name='software_version', default=NOTHING, validator=<instance_of validator for type <class 'cryptoparser.ssh.version.SshSoftwareVersionBase'>>, repr=True, eq=True, eq_key=None, order=True, order_key=None, hash=None, init=True, metadata=mappingproxy({}), type=None, converter=None, kw_only=False, inherited=False, on_setattr=None), <class 'cryptoparser.ssh.version.SshSoftwareVersionBase'>, 'DHEater_0.3.1')

this is on Python 3.10.1 on macOS ARM with the following package versions:

asn1crypto==1.4.0
attrs==21.4.0
certifi==2021.10.8
certvalidator==0.11.1
charset-normalizer==2.0.11
cryptolyzer==0.8.0
cryptoparser==0.8.0
idna==3.3
oscrypto==1.2.1
python-dateutil==2.8.2
requests==2.27.1
six==1.16.0
urllib3==1.26.8

bug

opened by Nothing4You 0

Using IPv6

Hi,

I am trying to use dheater with an IPv6 address but I always get an error like below:

python3 -m dheater --protocol tls "[3011::4]:5060"
Network error oocuerd while checking whether Diffie-Hellman ephemeral (DHE) key exchange is supported by the server; uri="[3011::4]:5060", error="address of the target cannot be resolved"

How should I use or is it some kind of bug?

opened by VidarHUN 0