[imp] Fwd: E-mail address spoofing with RLO

[ANANT S ATHAVALE]

Hello,

Thanks for the info.

Regards,
ANANT.

----- Message from jan at horde.org ---------
     Date: Wed, 25 May 2011 13:55:23 +0200
     From: Jan Schneider <jan at horde.org>
  Subject: Re: [imp] Fwd: E-mail address spoofing with RLO
       To: imp at lists.horde.org


> So, basically what this says is, that you can't trust an email's  
> sender name? Suprise. Of course IMP is affected to, any client that  
> properly displays Unicode is affected.
>
> Zitat von ANANT S ATHAVALE <asa at isac.gov.in>:
>
>> Dear List,
>>
>> Can anybody confirm, IMP is not affected by this?
>>
>> -ANANT.
>>
>>    Date: Tue, 24 May 2011 18:58:19 +0200
>>    From: Wouter Coekaerts <wouter at coekaerts.be>
>> Subject: E-mail address spoofing with RLO
>>      To: bugtraq at securityfocus.com, full-disclosure at lists.grok.org.uk
>>
>> E-mail address spoofing with RLO - http://wouter.coekaerts.be/2011/email-rlo
>>
>> Introduction
>> =============
>> When we reply to an e-mail, the address we see in the To-field serves
>> a purpose beyond getting our answer back to original sender. We attach
>> a meaning to these addresses. If we see john.smith at example.com, we
>> expect that we're really sending a mail to someone at the Example
>> company.
>> We may have learned not to trust the "From" address: that's about as
>> unreliable as the return address on the back of an envelope. But we
>> should be careful with what we think we see in To-field too.
>>
>> Problem
>> =======
>> The problem comes from the unicode "right-to-left override" (RLO,
>> U+202E) character. It's an invisible character, that forces the text
>> after it to be treated as right-to-left. For example "abc[RLO]def" is
>> displayed as "abcfed". It's well known that these kind of characters
>> have security implications[1][2], it has led to other problems[3]
>> before, and this is a new one in that category:
>> It can be abused to display an E-mail address backwards, so that it
>> appear to be on a different domain than it actually is.
>>
>> Details
>> =======
>> An RLO is usually not accepted in an address, but it is accepted in
>> the display name. The display name and the address are often shown
>> together, allowing the RLO in the display name to affect how the
>> address is shown. For example, "Firstname Lastname [RLO]
>> <moc.mitciv at attacker.com>" is displayed as "Firstname Lastname
>> <moc.rekcatta at victim.com> ".
>>
>> This can not be used to spoof arbitrary addresses because the
>> attacker's reversed real domain is still in it. But it can be used to
>> spoof any domain. And a well chosen domain name reversed can look like
>> a convincing foreign real name in the first part of the address.
>> This problem is worse than spoofing of the From-addresses, because an
>> attacker can have a whole conversation without an indication to the
>> victim that he's not who (from the domain) he pretends to be.
>>
>> Affected software
>> =================
>> This affects most e-mail clients. These are the ones I tested, and
>> whose vendors have been made aware of this in 2009.
>> * Gmail: still vulnerable
>> * Hotmail: Fixed in February 2010 [4]
>> * Outlook 2007 (and later?): no fix announced, presumably still vulnerable
>> * Outlook Web Access: no fix announced, presumably still vulnerable
>> * Evolution: still vulnerable (Bug 601172 [5])
>> * KMail: Fixed since December 2009, KDE 4.2.x (never released),  
>> 4.3.5 and 4.4.0
>> * And more...
>>
>> 1: http://unicode.org/reports/tr9/#Explicit_Directional_Overrides
>> 2: http://unicode.org/reports/tr36/#Bidirectional_Text_Spoofing
>> 3: http://www.mozilla.org/security/announce/2009/mfsa2009-62.html
>> 4: http://technet.microsoft.com/en-us/security/cc308575.aspx#0210
>> 5: https://bugzilla.gnome.org/show_bug.cgi?id=601172
>>
>>
>> Regards,
>>
>> Anant Athavale.
>>
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>
>
> Jan.
>
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----- End message from jan at horde.org -----



Regards,

Anant Athavale.

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