Corporate Web based email - threats

[Pavel <hiddenrecipient () email com>]

Hi all,

The access to corporate web mail services like OWA, iNotes or VPN SSL stuff is becoming increasingly popular. I saw 
many posts here about security measures for protecting Web server itself, filtering viruses and encrypting data in 
transit. However, few people address a problem of temporary content stored on client PCs and stolen 
session/credentials. Given that companies are looking for more mobility, the typical use of webmail services occurs on 
public PCs, kiosks and Internet cafés. 

1. Temporary content. Some Web based email and VPN SSL clients have features to remove temporary files from the client 
PCs. The tests we performed (iNotes and OWA) show that the cleaning is very poor and a lot files and attachements are 
still sitting in the IE cache, Temp folder, Acrobat cache, different download managers like Mozilla or Reget/Getrigt 
etc. The cleaning is ever worse on any PC that have non standard OS (Linux, Mac etc.) and browsers like Firefox, Opera 
and so on.

2. Stolen session. Some vendors recommend to use SecurID tokens or stuff like that to prevent stealing users' 
credentials. However, there is still a lot of possibility to penetrate user sessions starting from stolen session IDs 
thru a malicious email to different sorts of "parent control" software (keylogger + file/clipboard/web pages sniffer + 
screenshots every 15 seconds ...). One never khows what is running on that regular public PC.

I would like to hear from you any ideas on how did you mitigate these risks and what was your reasonong to 
allow/disallow the access to your company's webmail.

Thank you in advance


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