Author: Andrew Calafato a ndrewlafato@ace-tech.eu

1. An analysis of the vulnerabilities introduced with Java Card 3 Connected Edition Supervisor: Dr.KostantinosMarkantonakis Author: Andrew Calafato andrew.calafato@ace-tech.eu 2012 Royal Holloway, University of London

2. Contents • Smart cards & their usages • Smart Card Operating Systems/Platforms (Java Card) • Attacks on Smart Cards • Java Card 3 Connected Edition – new features, new threats

3. Smart cards • Pocket-sized devices with an embedded integrated circuit chip (ICC) and secure storage • Microcontroller: offers a secure processing environment (encryption, integrity, authentication and other security services) • Memory: to store information in a tamper-resistant security system, (protecting confidentiality and integrity of data) • RAM – volatile (non-persistent) - computation working space • EEPROM/Flash - non-volatile - data storage, applications loaded after issuance • ROM – non-volatile read-only memory programmed during manufacture – OS & permanent data • Form factors: • plastic cards • subscriber identity modules (SIMs) - like ones in mobile phones • USB-based tokens • Fobs • Contact smart cards - contact pads in direct contact with the reader for power and data communication • Contactless smart cards – power and communication through antennae using radio frequencies (RF)

4. Smart card Usages • Mobile phone SIM card (Subscriber Identity Module) • Credit/Debit Cards with a chip (chip-and-pin) • Health cards • Pay-TV cards • Contactless travel cards • Access/identity cards • EurosmartSmart cards market figures forecast for 2012 (in Millions of Units): Contact Contactless

5. Contents • Smart cards & their usages • Smart Card Operating Systems/Platforms (Java Card) • Attacks on Smart Cards • Java Card 3 Connected Edition – new features, new threats

6. Operating Systems & Platforms monolithic embedded in chip by manufacturers Rigid architecture • modular architecture • hardware management • application level modules • target application Shorter time to market Software reuse Standard platforms adaptable using filters (e.g. SIM cards) Some flexibility • Open Platforms: • Embedded h/w management layer • VM for platform independence • Multiple apps installed after issue Multi-application execution platforms Java Card, MULTOS, SmartCard.NET

7. Java Card

8. Contents • Smart cards & their usages • Smart Card Operating Systems/Platforms (Java Card) • Attacks on Smart Cards • Java Card 3 Connected Edition – new features, new threats

9. Smart card Physical Attacks (Hardware) • Probing bus with microprobes • Focused Ion Beams & laser cutters to cut/short circuit • Extreme environment - temperature, light, ionized radiation, high frequency rays, etc. (semi-invasive) • E.g. Clock signal / power supply / external electrical field transients to create glitch attacks to deliberately alter memory locations. • Combined with mathematical and statistical analysis to compromise integrity and confidentiality of data - e.g. a number of papers on applying Differential Fault Analysis (DFA) for key retrieval • Countermeasures • programmable active shielding covering the whole chip • sensors, such as infra-red, ultra-violet or visible light sensors, filters • internal voltage, glitch and temperature sensors • proprietary timing and chip layout • scrambled memories and busses (also dynamic per session using scramblers) • software-based countermeasures against fault induction – e.g. integrity checks

10. Smart card Physical Attacks (Side-channel) • Non-intrusive attacks based on the analysis of information achieved through covert channels to gain information on algorithms/keys • timing information • electromagnetic radiation • power consumption • Simple Power Analysis (SPA) - power consumption analysis during program execution • Differential Power Analysis (DPA) - power consumption analysis over known sets of data vs. some unknown input & statistical extrapolation (algorithm can be unknown) • High-Order Differential Power Analysis (HO-DPA) - signal readings from multiple data sources, using different measuring techniques and different time offsets • Countermeasures • frequency monitoring sensors to avoid clock speed reduction • fast voltage regulators to de-correlate power consumption from instruction execution • introduction of random noise and random wait states • current scrambling/stabilizing techniques • design cryptographic algorithms susceptible to Timing Analysis Attacks • random delays / random ordering of code execution • exclusive use of instructions with similar power consumption

11. Smart card Logical Attacks • Can be targeted at the system /infrastructure that the smart card in part of • Can be launched throughout the whole life cycle of the smart card • accidental/deliberate tampering or disclosure of card design, architecture and layout • load Trojan horse & malicious applets • software vulnerabilities such as buffer overflows in all software layers • design and choice of cryptographic algorithms, protocols and key sizes (COMP128 & A5) • man-in-the-middle attack between card and card-reader (EMV protocol) • replay attacksagainst Static Data Authentication mechanisms • tearing attacks - card is powered off during processing leaving card in an inconsistent or invalid state, or omitting part of the operation such as incrementing the retry counter • Countermeasures • distribution of knowledge to protect from insider threat • physical security to protect from outsider threat • security-relating training and awareness programs for social engineering attacks • software development based on software engineering principles including testing • OS, virtual machines and applications susceptible to timing analysis

12. Smart card Combined S/w & H/w Attacks • A number of papers oncombining fault injection with logical attacks • Example 1 • Power analysis to locate VM type-checking moment in time (class cast exception) • Laser beam to ignore the exception thrown • => bypass runtime verification • => reference forgery => access memory locations inside application firewall boundary => code injection and alteration • Example 2 • Fault injection to alter Java Card operand stack value • => corrupt conditional branching • Example 3 • Alter return address of current function on stack to execute malicious bytecode • Example 4 • Replacing Java Card opcode with a NOP opcode (represented as 00) to skip instructions • Countermeasures • Same as ones discussed in fault attacks

13. Contents • Smart cards & their usages • Smart Card Operating Systems/Platforms (Java Card) • Attacks on Smart Cards • Java Card 3 Connected Edition – new features, new threats

14. 1. Complexity Virtual Machine Runtime Environment Applets & Web Applications Security systems card is part of all more complex harder to manage/model security

15. 2. Multithreading • Parallel execution of processes in web application and extended applet environments • Amultithreaded runtime environment – can service multiple incoming requests concurrently & perform multiple executions in parallel • Inherent complexity of concurrency • threads interact & intervene with each other (e.g. shared data) • nondeterministic executions • logging and debug information lead to different execution order • More difficult to test and model security (ensure correctness) • Denial of Service • deadlock– treads waiting while attempting to acquire each other's locks • high priority threads cause other threads to starve • Race conditions • Explained in next slide • Need to access shared data atomically – use locks • Time-of-check to time-of-use (TOCTTOU) • Example in next slide • Need to check as close as possible to use • Preferably make check immutable (check and use in an atomic operation)

16. Race condition

17. Time-of-check to time-of-use (TOCTTOU) publicvoidsetBalance(finalBalanceRefbalanceParam) { //check phase if (balanceParam.getBalance() < 0) { thrownewIllegalArgumentException("Balance cannot be -ve"); } //reference parameter value can change during this time //use phase this.balance = balanceParam.getBalance(); }

18. 3. Web Applications • A subset of Java Servlet Specification v2.4 is supported => smart cards can host web applications • Expanded attack surface • HTTP & HTTPS connections (together with APDU) • ports outward facing the network / WWW • More URIs & application services available • All network layer attacks • Injection Attacks • Attacker injects untrusted data which ends up being executed unintentionally by an interpreter (HTML, Xpath, etc) – e.g. comment injection • Path manipulation / traversal • Crafting of URL/input to access files & additional capabilities • use ‛dot-dot-slash (../)’ sequences to move up to parent directories • Cross-Site Scripting • Injection of active content - client-side script (e.g. JavaScript, ActiveX, VBScript, Flash, etc) • Reflected – e.g. trick user to follow a link injecting script • Stored/Persistent – e.g. forum / social media • DOM Based – script act on DOM objects - does not involve server at all

19. ... 3. Web Applications • Cross Site Request Forgery (CSRF) • Try to force an authenticated victim to send a forged HTTP request to a vulnerable application • Step 1. Attacker forges a request in a way that is acceptable by the target server • Step 2. Trick victim to submit the information through a forged request while authenticated • Prevention: Synchronizer Token – nonce set to rendered page to be submitted back with request • Insecure Direct Object Reference • Request parameters altered ‘manually’ to reference protected resources • Prevention: authorization • Failure to Restrict URL Access • Whole URL is manually crafted to access protected resources • Other attacks/vulnerabilities • DoS (card has restricted environment) • HTTP Response Splitting • Man-in-the-Browser • Session Management vulnerabilities • … Prevention: Input validation of any untrusted data Escape/sanitize before parsing Authentication & Authorization Etc.

20. Other Features • Dynamic class loading • Application can load a class dynamically at runtime as opposed to explicitly imported • complicates the type safety enforcement process significantly • can load class with malicious code • attacks by Barbuet al. exploited dynamic class loading to create • ill-formed code injection attacks • illegitimate modification of applications • circumvent application firewall • Inter-application communications • Interactions between applications through the application firewall • Object can offer services to other applications • notification mechanism using events • Larger attack surface • Features can be use in more sophisticated attacks (e.g. Barbu et al.)

21. Other Features • Network Communications (Generic Connection Framework) through high speed interfaces (e.g. USB) • TCP/IP, HTTP, SSL/TLS , File Connections, etc • exposed to attacks targeted at all lower Network Layers • connected for prolonged period of times • Garbage collector • Process reclaiming unreferenced data • Another process which can be exploited by attackers (e.g. Barbu et al.)

22. Questions?