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This article by Prof. Ravi Sandhu discusses the ongoing problem of online identity authentication and the vulnerabilities of existing security measures. It explores the need for stronger authentication methods to combat phishing and man-in-the-middle attacks.
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Protecting Online Identity™ Authentication: the problem that will not go away Prof. Ravi Sandhu Chief Scientist sandhu@tricipher.com 703 283 3484
The State of Cyber Security • We are in the midst of big change • Nobody knows where we are headed • Conventional wisdom on where we are headed is likely wrong
Security Schools of Thought • OLD THINK: We had it figured out. If the industry had only listened to us our computers and networks today would be secure. • REALITY: Today’s and tomorrow’s cyber systems and their security needs are fundamentally different from the timesharing era of the early 1970’s.
Stand-alone mainframes and mini-computers Internet Mutually suspicious security with split responsibility Enterprise security Few and standard services Many and new innovative services Vandals Criminals Change Drivers
Authentication Characterized Authentication • is fundamental to security • is hard Authentication can enable • single sign on (or reduced sign on) • digital signatures
Authentication Sliced • Something you know • Passwords, Personal facts • Something you have • Smart card, One-Time-Password generator, PC … • Something you are • Fingerprint, Iris, DNA, Voiceprint, … • Multifactor = 2 or more of these • Leap to 2-factor from 1-factor provides biggest gain • 2 factors typically from different categories above
Authentication Sliced Differently: Take 1 • Shared secrets versus public-private keys • Shared secrets do not scale, especially across administrative domains • Shared secrets do not facilitate single sign-on • The holy grail of public key infrastructure continues to offer the best hope for scalability and single sign-on • Mostly true BUT don’t forget • Kerberos, symmetric key single sign-on within an enterprise • ATM network
Authentication Sliced Differently: Take 2 • One-way authentication versus mutual authentication • One-way authentication is the norm • It is particularly susceptible to phishing • One-time passwords are susceptible to MITM attacks due to lack of mutual authentication
Strong Authentication • Two-factor (or multi-factor) • Mutual authentication
Weak User Authentication Strong User Authentication Transaction Authentication Existing Authentication Methods & Threats
Why Are These Security Measures Vulnerable? • Authentication technologies are vulnerable to MITM Phishing 2.0 attacks when: • They rely on weak, easily spoofable information • They rely on ‘shared secrets’ • They use only one-way SSL security • Vulnerable Authentication Technologies : • IP Geo, Device Fingerprint, OTP Tokens, Scratch Cards, Grid Cards, Cookies, Text, and Pictures
Man-in-the-Middle Attacks Are Happening A man-in-the-middle attack (MITM): attacker is able to read, insert and modify transactions between two parties without either party knowing that the link between them has been compromised. • CitiBank Attack: • July 10th, 2006 • Defeated OTP Tokens • 35 MITM Sites in Russia • Amazon Attack: • January 3rd, 2007 • Defeated Username/Password • Bank of America: • April 10th, 2007 • Defeats Sitekey Cookie/Picture (Movie) • ABN AMRO: • April 20th, 2007 • Defeats OTP Token
The Citibank Attack Decrypted Links to fake CitiBusiness login page, hosted in Russia by Tufel-Club.ru and routed through botnet. Phishing email Inputs and steals users’ credentials (including Token code) in real time at the actual CitiBusiness.com site Attacker changes transaction or executes a new transaction
IP Spoofing Story • IP Spoofing predicted in Bell Labs report ≈ 1985 • 1st Generation firewalls deployed ≈ 1992 • IP Spoofing attacks proliferate in the wild ≈ 1993 • VPNs emerge ≈ late 1990’s • Vulnerability shifts to accessing end-point • Network Admission Control ≈ 2000’s
Evolution of Phishing • Phishing 1.0 • Attack: Capture reusable passwords • Defense: user education, cookies, pictures • Phishing 2.0 • Attack: MITM in the 1-way SSL channel, breaks OTPs • Defense: 2-way SSL • Phishing 3.0 • Attack: Browser-based MITB client in front of 2-way SSL • Defense: Transaction authentication outside browser • Phishing 4.0 • Attack: PC-based MIPC client in front of 2-way SSL • Defense: Transaction authentication outside PC, PC hardening
Sandhu’s Laws of Attackers • Attackers exist • You will be attacked • Attackers have sharply escalating incentive • Money, terrorism, warfare, espionage, sabotage, … • Attackers are lazy (follow path of least resistance) • Attacks will escalate BUT no faster than necessary • Attackers are innovative (and stealthy) • Eventually all feasible attacks will manifest • Attackers are copycats • Known attacks will proliferate widely • Attackers have asymmetrical advantage • Need one point of failure
Sandhu’s Laws of Defenders • Defenses are necessary • Defenses have escalating scope • Defenses raise barriers for attackers • Defenses will require new barriers over time • Defenses with better barriers have value • Defenses will be breached
Sandhu’s Laws of Users • Users exist and are necessary • Users have escalating exposure • Users are lazy and expect convenience • Users are innovative and will bypass inconvenient security • Users are the weakest link • Users expect to be protected
Operational Principles • Prepare for tomorrow’s attacks, not just yesterday’s • Good defenders strive to stay ahead of the curve, bad defenders forever lag • Take care of tomorrow’s attacks before next year’s attacks • Researchers will and should pursue defense against attacks that will manifest far in the future BUT these solutions will deploy only as attacks catch up • Use future-proof barriers • Defenders need a roadmap and need to make adjustments • It’s all about trade-offs • Security, Convenience, Cost