Presentation on theme: "1 Rethinking Password Strategies Ravi Sandhu Chief Scientist 703 283 3484"— Presentation transcript:
1 Rethinking Password Strategies Ravi Sandhu Chief Scientist
2 Outline Security doctrine for the 21 st century Password vulnerabilities and countermeasures Available technologies
3 Secure doctrine for the 21 st century Good enough security –Absolute security is not possible –Too much security is counterproductive –Too little security is not acceptable –The goal is to find the sweet spot Security dollars must work smarter and harder –Security threats are growing –Security budgets are flat and expertise is shrinking –Need more bang for the buck Prevent catastrophic failure and tolerate sporadic isolated failures –Focus on preventing catastrophic failure –Tolerate sporadic isolated failures
4 The threat environment is getting worse Illegal modems, floppy-viruses, insider theft Info Web sites, firewalls, -viruses, insider theft Online web sites, IDS, worms, insider theft XML, disappearing boundaries, insider theft Claim: The potential threat has gone up hundredfold. RISK
5 Resources and expertise are not growing Dollars devoted to problem Skilled resources to address the problems
6 Work smarter and harder Starting point: –Risks went up 100 fold –Security dollars went up a little –Skilled resources went down So what could happen? Option: Your security budget goes up enormously Reality: Security budget stays flat as % of IT budget. The security dollars have to work smarter and harder!
7 Some thoughts on smarter... Proposition: We waste dollars on non/small problems (the 20/80 rule of security!) Example: Unnecessary encryption (40 bit vs. 128 bit SSL) Explanation: –Security has many roots in the cold war era. The communication link was the problem. In our world the end points are a MUCH bigger problem. So why do we waste so many dollars encrypting links unlikely to be attacked? Challenge spending on non-problems
8 Some thoughts on smarter... Proposition: We are vulnerable to peer pressure. Sometimes our peers are just wrong. Example: Bank B has to deploy technology/policy X because Bank A did so. And then Bank C, Bank D... Soon weve spent scarce dollars on technology/policy of doubtful value. (e.g. password aging) Explanation: Its hard to buck a so-called best practice in our business, even if the evidence is lacking. Challenge best practices
9 Some thoughts on smarter... Proposition: the vendor crypto-techno-geeks lead us by the nose. Example: The entire PKI fiasco. How much did we spend? What value have we seen? Who told the crypto-geeks that they decide what sort of digital signatures are legal? Explanation: Security is an obscure science where you are trying to prove the negative. Its hard to question the crypto- experts in their Ivory Towers. Challenge the geeks
10 Some thoughts on smarter... Proposition: Vendor business models drive our infrastructure, as opposed to our needs. Example: Why do SSL certificates expire annually causing us outages? Who determined that a technology company can better manage a certificate authority infrastructure than a bank that secures tens of billions of dollars? Explanation: FUD (Fear-Uncertainty-Doubt) Challenge vendor business models
11 Some thoughts on harder... Proposition: Security products must address your lack of skilled resources issue. Example: Many products need experts to set up and run them. Explanation: Most products are designed by the experts for the experts. They do not realize that most products are run by non-experts with little time to get trained on everything. Ask: Can a reasonably competent systems/network person with little security experience run the product?
12 Some thoughts on harder... Proposition: Security products must be defensive Example: Many security products work great as long as those operating them walk on water and dont get their feet wet. Explanation: Designed by security geeks whove never lived in a real operational world. Ask: Can an average person having a real bad day, be woken at 2AM to fix an issue without opening up a major hole inadvertently?
13 Some thoughts on harder... Proposition: Security products must address fundamental problems, before the esoteric. Example: Weak passwords are a major critical problem. Why spend money on esoteric new problems before this is fixed? Explanation: The fundamental problems are often not sexy. Ask: Before securing the attic window, we should get a better lock on the front door!
14 Some thoughts on harder... Proposition: To get more from your security dollars, a security product must solve multiple problems. Example: One product for passwords, one for PKI, one for 2- factor, one for signatures... (and thats for the Internet, lets get even more for wireless...) Explanation: Vendors address niches. Your business sees the big picture. Ask: Can I reuse the product, for multiple functions across multiple channels?
15 Outline Security doctrine for the 21 st century Password vulnerabilities and countermeasures Available technologies
16 A Common Misperception Fact: Password based systems are often vulnerable to attacks Myth: Passwords are inherently insecure. Fact: It is completely possible to design a sufficiently secure password system. Fact: A sufficiently secure password system must use some form of PKI under the covers –This is a mathematical theorem proved in 1998 Designing sufficiently secure password-based systems is non-trivial but it is possible by proper use of PKI under the covers.
17 Another Common Misperception Fact: Users hate current password systems that require –too many passwords and –force too many changes Myth: Users inherently hate passwords. Fact: It is completely possible to design a user friendly password system with PKI beneath the covers Designing user-friendly and sufficiently secure password-based systems is non-trivial but it is possible by proper use of PKI under the covers.
18 Yet Another Common Misperception Myth: Security is increased by forcing users to change their passwords frequently Fact: There is no empirical evidence to show this and much anecdotal evidence to show the opposite –Changing passwords too frequently will degrade security because of user reaction A strong password-based system should not force frequent password changes
19 Password Vulnerabilities and Countermeasures End-user Vulnerabilities –User education and awareness –Technology can help mitigate some (but not all) of these Sniffing Attacks –Everything on the wire should be encrypted Server Spoofing Attacks –Need server authentication Guessing Attacks: online –Prevented by throttling Guessing Attacks: offline (Dictionary attacks) –Prevented by PKI encryption on the wire and hardened password server on the backend
20 End-user Vulnerabilities Poor password selection –Users choose easy-to-guess passwords –Countermeasure: enforce complexity rules Passwords written down by users –Infrequently used passwords are often written down –Countermeasure: reduce number of passwords a user needs to remember Password shoulder surfing –Password exposed to observant bystander –Countermeasure: user awareness Password reuse across multiple servers –Password becomes vulnerable at weak servers –Countermeasure: user awareness
21 End-user Vulnerabilities Password sharing –Users will share passwords with others only if there is no personal risk –Countermeasure: personal risk must be injected into the system (perhaps by policy and procedure) Password reset costs –Users forget passwords –Countermeasure: automate password resets BUT be careful not to reduce security too much Undetected theft –Users are not aware if their passwords are compromised –Countermeasure: detection technology and feedback to the user
22 Sniffing attacks Sniffing on the wire is easily prevented by widely deployed technologies such as SSL and IPSEC –No excuse for letting this happen anymore Sniffing on the desktop by malicious code –Password exposure is limited to a single user –Users need to be free of viruses, worms and Trojan horses for all kinds of reasons –Windows 2000, Windows XP allow tighter control of the desktop by the organization –Ultimately we need stronger platforms that reduce the risk of malicious code
23 Server-spoofing attacks To prevent server-spoofing we need server authentication and user awareness –SSL with server-side certificates is a good enough and widely deployed solution for this problem In future we can move to solutions where the password is never communicated to the server –SSL enhanced with password-based client-side certificates is the most promising technology –Need a footprint on the desktop
24 Guessing Attacks: online Attacker tries various passwords until he succeeds –Slow down (throttle) the rate at which an attacker can try different guesses –Many strategies are used in practice 3 strikes and lock the account for password reset 3 strikes and lock the account for some time Slowdown each successive guess –Aggressive strategies can lead to denial of service to legitimate users –Loss is limited to small number of passwords
25 Guessing Attacks: offline aka Dictionary Attack Attacker obtains encrypted password Attacker tries passwords from a dictionary of commonly used passwords and compares with encrypted password –Encrypted password is often salted to make this harder Various studies have shown that 25% to 50% of passwords fall to this attack –This is catastrophic failure In the past these attacks would take months, with current processor speeds they take hours or days or even less We are at the point where exhaustive search is feasible so even a dictionary is not needed This is the single biggest vulnerability in most existing password systems and it leads to catastrophic failure
26 Guessing Attacks: offline aka Dictionary Attack How to prevent: old approach –Force user to select passwords that withstand dictionary attack Record shows that this is easier said than done Trend is that exhaustive search on entire space of human- memorizable passwords is feasible –Password aging to force a change every 30 days or so Would need to age much faster than 30 days to have any effect on feasibility of attack –Hide password files (e.g. shadow files) Old solution dating to when users had access to system; current end users usually dont have access to system. Meaningless against hackers and admin account compromise –Harden password system OS Very hard to maintain in hardened manner. admin accounts tend to have carte-blanche access. Too many insider accounts.
27 Guessing Attacks: offline aka Dictionary Attack How to prevent: modern approach –Make password system OS very hard to penetrate. –Use least privilege based partitioning to sharply minimize or eliminate insider account attacks. –Use PKI technology to eliminate traditional encrypted password file –Make it non-invasive to end-user (zero client footprint, pure back-end solution). –Make it very easy to integrate with existing systems (e.g. IBM WebSeal, Netegrity, LDAP, Active Directory, etc.)
28 Outline Security doctrine for the 21 st century Password vulnerabilities and countermeasures Available technologies
29 Support multiple security levels on a single infrastructure Weak Password Systems, Catastrophic Dictionary attacks Zero Footprint Hardened Password Roaming PKI No change for users No change for issuer No password file (PKI hardened) Password Usability PKI Security Password plus USB token or variant Secure Identity Appliance TM Two-factor PKI
30 2-Key RSA vs. 3-Key RSA: Hardened Passwords 2-Key RSA Keys: a)Alice Public = e b)Alice Private = d c)Alice Cert = C Challenge/Response: a)Challenge sent b)Response signed with d c)Verified with e and C Observation: Guessing d from e is extremely difficult. 3-Key RSA Keys: a)Alice Public = e b)Alice Private = d –Alice has D1=PKCS5(password) –Appliance has D2 c)Alice Cert = C Challenge/Response: a)Challenge sent b)Response signed with D1 c)Verified with D2, e and C Observation: Guessing D1 from D2 is extremely difficult.
31 Hardened Operating System Redundant very high availability architecture Powerful monitoring ability (SNMP based) SIA Solution – How it works Appliance Architecture Compartmentalized System Systems Partition Security Admin Partition User Admin Partition User Private Data Partition Indepe- pendent Audit Controls 3-Key RSA Key 1: Derived from Password Key 2: Verification/Co-Signing Key on Appliance Key 3: Traditional Verification Public Key PKI hardened passwords