Instant Messenger Security with a focus on implementing security policies in corporate IM services Kaushal S Chandrashekar CS 691 Dr. Edward Chow UCCS

Outline Instant Messaging Problems with IM in corporate environments General threats to IM Implementing security policies in IM Design details and problems Summary References

Instant Messaging Instant Messaging (IM) is the online chat medium that allows people to connect and collaborate in real-time. Based on IP protocols 10 million enterprise users in 2002 Expected to explode up to 180 million users by 2007

Problems with Free IM in corporate environments Privacy concerns Security Concerns No central administration No integration with corporate IT Security and firewall problems Dependence on external infrastructure providers

General threats to IM Worms Bypasses most anti-virus scanners Can resend itself to all on the buddy list Backdoor Trojan Horses Utilize IM app to send information about user Can modify configuration settings to make whole HDD available for file sharing

General threats to IM Contd Hijacking and Impersonation Account information can be stolen and misused Man-in-the-middle attacks Denial of Service Flood attacks

Implementing security policies in IM Why? Most enterprise IMs provide only primitive control A more fine-grained approach required Common breaches of security Transfer of confidential files to unauthorized users Unauthorized attendees in confidential conferences Messages containing confidential information

Required features in corporate IMs Secure log-in Chatting Internal, application based External, web based Conferencing File sharing

Basic IM Service architecture Central Messaging Server Internal Network No external IP Protected against internal DOS attacks Client(s) Authentication Access Control Certificate handling Authentication Encryption DMZ Web Server Web based IM

Security Clearance hierarchy Mgmt Level 1 Mgmt Level 2. Regular Employee. Customer Support. External

Log-in Essential because it determines security clearance Password-locked certificates Problems Weak passwords Vulnerable to software cracking and social engineering Biometric keys Integration of IM login with terminal login

Chatting Rules External chat only with employees with Ls >= l k, a predetermined level If Ls(S1) >= Ls(S2), S1 can chat unchecked with S2, but messages from S2 to S1 are monitored All chat messages are encrypted using mutually negotiated session keys, except for ones with externals.

Chatting contd. Chat monitoring and logging All chat activity is monitored and logged to log files that are accessible only to any non-sysadmin users Suspect word list to raise alerts Problems Words split up, capitalized Sentences in unrecognized languages spelt in a recognized language IM activity at unusual times could raise alerts

Conferences Collaborative chatting with ability to record conversation by attendees as minutes Rules Each conference has security level assigned to level l If Ls(Employee) <= l, employee can read/write Custom invitations to conferences also possible Downgrading of conference level after starting possible, but is logged and all messages generated by users with higher security clearances will be hidden to less secure users

File Sharing All files that are shared are assumed to be at the senders security level Levels can be changed by the system administrator If Lo >= Ls, the file can be transferred All manuals and public documents are tagged in a central repository by the sys-admin with Lo >= Ls(External) so that customer service can transfer documents or parts of it to clients

Summary Conflict between restrictions imposed by security policies and ease of use built into IM services No security policy is a match for human ingenuity. Further research is required and perhaps a new model for enterprise IM services Unified messaging, currently getting popular, requires a extremely vast and diverse security policy.

References Computer Security – Art and Science by Matt Bishop