Author: Andrew Calafato [email protected] Supervisor: Dr. Kostantinos Markantonakis 2012 Royal Holloway, University of London An analysis of.

Author:Andrew [email protected]

Supervisor:Dr. Kostantinos Markantonakis

2012Royal Holloway, University of London

An analysis of the vulnerabilities introduced with Java Card 3 Connected Edition

Contents1. Smart cards & their usages2. Smart Card Operating Systems/Platforms

(Java Card)3. Attacks on Smart Cards4. Java Card 3 Connected Edition – new

features, new threats

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)

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

• Eurosmart Smart cards market figures forecast for 2012 (in Millions of Units):

OthersTransport

Pay TVGovernment - Healthcare

Financial ServicesTelecom

90

135

120

300

1260

5200

OthersTransport

Government - HealthcareFinancial Services

35

95

160

290

Contact Contactless

Contents1. Smart cards & their usages2. Smart Card Operating Systems/Platforms

(Java Card)3. Attacks on Smart Cards4. Java Card 3 Connected Edition – new

features, new threats

Operating Systems & Platformsmonolithic

embedded in chip by manufacturers

modular architecture• hardware management• application level modules • target application

Shorter time to marketSoftware 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 platformsJava Card, MULTOS, SmartCard.NET

Rigid architecture

Java CardApplets

Extended Applets Servlets

• Multiple Java Card applications• Applet container manages classic & extended ISO7816 APDU applets• Servlet container manages servlet-based web apps

Java Card Runtime Environment (JCRE)

Industry Add on Classes • Libraries providing services / refinements to security & system models

Java Card Framework

• API classes for • developing Java Card apps • providing system services to apps

• application management• transaction management• I/O communication • cryptographic functionality

Java Card Virtual Machine (JCVM)

• Executes byte code• Provides the functions accessible from outside, such as signature,

authentication and applications. • Controls access to smart card resources (memory, I/O, etc) • Secure loading of apps on card post-issuance• Hides manufacturer's proprietary technology with a common language

and system interface

O.S. & Native Functions Specific IC and native operating system implementation

Contents1. Smart cards & their usages2. Smart Card Operating Systems/Platforms

(Java Card)3. Attacks on Smart Cards4. Java Card 3 Connected Edition – new

features, new threats

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

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

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 attacks against 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

Smart card Combined S/w & H/w Attacks• A number of papers on combining 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

Contents1. Smart cards & their usages2. Smart Card Operating Systems/Platforms

(Java Card)3. Attacks on Smart Cards4. Java Card 3 Connected Edition – new

features, new threats

1. ComplexityVirtual MachineRuntime Environment Applets & Web ApplicationsSecurity systems card is part of

all more complex

harder to manage/model security

2. Multithreading• Parallel execution of processes in web application and extended applet

environments • A multithreaded runtime environment – can service multiple incoming requests

concurrently & perform multiple executions in parallelÞ Inherent complexity of concurrency

– threads interact & intervene with each other (e.g. shared data)– nondeterministic executions– logging and debug information lead to different execution orderÞ More difficult to test and model security (ensure correctness)

Þ Denial of Service– deadlock – treads waiting while attempting to acquire each other's locks– high priority threads cause other threads to starve

Þ Race conditions– Explained in next slide– Need to access shared data atomically – use locks

Þ 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)

Race conditionThread 1 – add 5 to shared balance Thread 2 – add 10 to shared balance

Read shared value (100)

Context Switch

Read shared value (100)

Add 10 to it (110)

Store value (110)

Context Switch

Add 5 to it (105)

Store value (105)

The +10 here has been overridden!

Time-of-check to time-of-use (TOCTTOU)

public void setBalance(final BalanceRef balanceParam) { //check phase if (balanceParam.getBalance() < 0) { throw new IllegalArgumentException("Balance cannot be -ve"); } //reference parameter value can change during this time //use phase this.balance = balanceParam.getBalance();}

3. Web Applications• A subset of Java Servlet Specification v2.4 is supported => smart cards can host

web applicationsÞ Expanded attack surface

– HTTP & HTTPS connections (together with APDU) – ports outward facing the network / WWW– More URIs & application services available– All network layer attacks

Þ Injection Attacks– Attacker injects untrusted data which ends up being executed unintentionally by an

interpreter (HTML, Xpath, etc) – e.g. comment injectionÞ Path manipulation / traversal

– Crafting of URL/input to access files & additional capabilities– use ‛dot-dot-slash (../)’ sequences to move up to parent directories

Þ 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

... 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 dataEscape/sanitize before parsingAuthentication & AuthorizationEtc.

Other Features4. Dynamic class loading

– Application can load a class dynamically at runtime as opposed to explicitly imported

Þ complicates the type safety enforcement process significantlyÞ can load class with malicious codeÞ attacks by Barbu et al. exploited dynamic class loading to create

• ill-formed code injection attacks • illegitimate modification of applications• circumvent application firewall

5. Inter-application communications– Interactions between applications through the application firewall– Object can offer services to other applications– notification mechanism using eventsÞ Larger attack surfaceÞ Features can be use in more sophisticated attacks (e.g. Barbu et al.)

Other Features4. Network Communications (Generic Connection

Framework) through high speed interfaces (e.g. USB)– TCP/IP, HTTP, SSL/TLS , File Connections, etcÞ exposed to attacks targeted at all lower Network LayersÞ connected for prolonged period of times

5. Garbage collector– Process reclaiming unreferenced dataÞ Another process which can be exploited by attackers (e.g.

Barbu et al.)

Questions?