guidelines on electronic mail security
DESCRIPTION
Guidelines on Electronic Mail Security. http://csrc.nist.gov/publications/nistpubs/800-45/sp800-45.pdf. Background. The process starts with Message composition Transmitted Mail server processing. Multipurpose Internet Mail Extensions (MIME). - PowerPoint PPT PresentationTRANSCRIPT
Information Networking Security and Assurance LabNational Chung Cheng University
Guidelines on Electronic Mail Security
http://csrc.nist.gov/publications/nistpubs/800-45/sp800-45.pdf
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Background
The process starts with Message composition Transmitted Mail server processing
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Multipurpose Internet Mail Extensions (MIME)
RFC 822: transmitting messages containing textual content
does not address messages that contain attachments MIME were developed
Audio Application Image Message Multipart
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Mail Transport Standards
To ensure reliability and interoperability among various email applications
Simple Mail Transfer Protocol (SMTP)
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Simple Mail Transfer Protocol Extensions
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Post Office Protocol
developed in 1984a way to copy messages from the mail server
mailbox to the mail clientRFC 918, nine commands were originally avai
lable for POP
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Internet Message Access Protocol
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Email-Related Encryption Standards
PGP and S/MIME Based on public key cryptography
symmetric key
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Pretty Good Privacy
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S/MIME
proposed in 1995 by RSA Data Security, Inc.S/MIME version 3
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Choosing an Appropriate Encryption Algorithm
Required securityRequired performanceSystem resourcesImport, export, or usage restrictionsEncryption schemes
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Key Management
difference between PGP and S/MIME PGP “circle of trust” S/MIME & some newer PGP “CA”
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Hardening the Mail Server Application
Securely Installing the Mail Server Securely Configuring Operating System and Mail Ser
ver Access Controls configure access controls Typical files to which access should be controlled are use the mail server operating system to limit files accessed by
the mail service processes. directories and files (outside the specified directory tree) cann
ot be accessed, even if users know the locations of those files. using a “chroot jail” for the mail server application To mitigate the effects of certain types of DoS attacks
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Protecting Email from Malicious Code
Virus Scanning at the firewall (application proxy) or mail relay The benefits weaknesses
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Protecting Email from Malicious Code
Virus Scanning on the mail server itself The benefits weaknesses Mail servers support
the integration of virus scanning at the mail server
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Protecting Email from Malicious Code
Virus Scanning on client hosts The benefits weaknesses Mail servers support
the integration of virus scanning at the mail server
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Unsolicited Bulk Email
unsolicited commercial email (UCE) or spam To control UCE messages open relay blacklists (ORBs)
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Miscs
Authenticated Mail Relay benefits Two methods
Secure Access Most protocols did not initially incorporate any form
of encryption or cryptographic authentication Transport Layer Security protocol RFC 2595
Enabling Web Access
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Using Mail Gateways
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Network Element Configuration
Router/Firewall ConfigurationRouters, stateful firewalls, proxy firewallsWhich portsRouter: network layer (packet filter) firewall