Penetration Testing mailing list archives
RE: DECODING EMAILS BETWEEN MS EXCHANGE AND A CLIENT
From: "Steve A" <pen.test.mail () logicallysecure org>
Date: Thu, 21 Jul 2005 22:50:27 +0100
Dan I am not aware there is one, also I have discovered that if the client is configured to use exchange (as opposed to smtp, pop or imapi) then the comms is done via DCE RPC (or so ethereal decodes it) - if you sniff the traffic you will find only this traffic. Some of the research I have done indicates that this RPC may be RC4 encrypted. This was sort of borne out by our sending of large files of known text (all 111's) but the result was not like cypher text - more of a double encoded type as there were noticable patterns in the cypher text. Steve A -----Original Message----- From: Dan Berberich [mailto:dan.berberich () gmail com] Sent: 21 July 2005 13:51 To: pen-test () securityfocus com Subject: re: DECODING EMAILS BETWEEN MS EXCHANGE AND A CLIENT Steve - funny, I'm currently working on the same problem. So far all I've got is doing a session capture and packed decode with ethereal. I have also exhaustively searched for a X.400 tool, but have so far found none. In my free time I might be planning to write a parser to extract just the packet payload, but I'm a little out of free time at the moment. -dan Steve said: We currently have a task that requires us to perform a capture of emails between an MS Exchange server and a MS Office Outlook (x400) client. I recognise a dirth of SMTP and POP sniffing programs out there but nothing seems to be able to decode the DCE RPC encoding/encryption of the exchange client communications. Is there anyone out there with knowledge of a product that will allow these emails to to captured and monitored. Oh before anyone suggests any exchange resident software, that option is out, we need to be external of the server and not a member of the domain - just sniffing the stuff as it goes by. Alternatively, does anyone know of a tool that will allow me to crack the RPC encryption/encoding to see the email in clear before I replay it to a server for keyword monitoring purposes? Oh the architecture is a 200 server with exch 2003 and a XP client with Office 2002 (incase that matters/helps) All tips gratefully received. Steve A steve<at>logicallysecure.org
Current thread:
- re: DECODING EMAILS BETWEEN MS EXCHANGE AND A CLIENT Dan Berberich (Jul 21)
- RE: DECODING EMAILS BETWEEN MS EXCHANGE AND A CLIENT Steve A (Jul 21)
- <Possible follow-ups>
- RE: DECODING EMAILS BETWEEN MS EXCHANGE AND A CLIENT Dan Berberich (Jul 22)