Published on March 22nd, 2019 📆 | 6667 Views ⚑0
Java Card VM Memory Safety
Security Explorations has discovered multiple security vulnerabilities in the reference implementation of Java Card technology from Oracle used in financial, government, transportation and telecommunication sectors among others. As for the impact, the vulnerabilities found make it possible to break memory safety of the underlying Java Card VM. As a result, full access to smartcard memory could be achieved, applet firewall could be broken or native code execution could be gained.
Hello All, We discovered multiple security vulnerabilities in reference implementation of Java Card technology  from Oracle used in financial, government, transportation and telecommunication sectors among others. According to Oracle, "Java Card technology provides a secured environment for applications that run on smart cards and other trusted devices with limited memory and processing capabilities. With close to six billion Java Card-based devices deployed each year, Java Card is already a leading software platform to run security services on smart cards and secure elements, which are chips used to protect smartphones, banking cards and government services" . Unfortunately, due to certain architectural choices from the past, it's hard to perceive Java Card technology in terms of security. There are ways for malformed applications loaded into a vulnerable Java Card to easily break memory safety. Such a breach directly leads to the security compromise of a Java Card VM, applet firewall breach and jeopardizes security of co-existing applications. In some cases, whole card environment can be compromised, but that's dependant on the underlying OS / processor architecture (i.e. presence of the flat address space, isolation between tasks). We were able to verify 18 of the issues in the environment of the most recent Java Card 3.1 software from Jan 2019 (Oracle Java Card VM reference implementation in the form of a simulator). One issue was specific to Gemalto  cards. These cards could not be immediately exploited with the use of our "favorite" issue found in Oracle reference implementation, so there was a need to find and use another one (which we did). As for the impact, the vulnerabilities found make it possible to break memory safety of the underlying Java Card VM. As a result, full access to smartcard memory could be achieved, applet firewall could be broken or native code execution could be gained. We verified this impact for the following Gemalto SIM cards: - GemXplore 3G V3.0-256K - 3G USIMERA Prime While none of the exploit codes can successfully pass off-card verification process, the vulnerabilities should be still perceived in terms of a significant weak point of given Java Card VM implementation. The reasons are the following: - the vulnerabilities could be used to compromise security of trusted chips used by financial, government and telecommunication sectors, this paves the way for their in-depth analysis , which can result in a discovery of far more serious issues, - Java Card thrives to provide secure environment for multiple applications (applets), as such no malicious application should be able to compromise security of the other one, - split verification process is a known architectural / design weakness of Java Card, the environment should at least provide memory safety if type safety cannot be guaranteed (type safety is a direct consequence of memory safety), - the nature of the issues undermine trust to Java Card as a secure environment and software platform eligible to run security services on smart cards and secure elements. It should be emphasized that successful loading of a malicious applet into target card requires either knowledge of the keys or existence of some other means facilitating it (a vulnerability in card OS, installed applications, exposed interfaces, etc.). Such scenarios cannot be excluded though. On Mar 20 2019, Security Explorations sent vulnerability notices to Oracle and Gemalto containing detailed information about discovered vulnerabilities. Thank you. -- Best Regards, Adam Gowdiak --------------------------------------------- Security Explorations http://www.security-explorations.com "We bring security research to a new level" --------------------------------------------- References:  JAVA CARD TECHNOLOGY https://www.oracle.com/technetwork/java/embedded/javacard/overview/index.html  Oracle Java Card Boosts Security for IoT Devices at the Edge https://www.oracle.com/corporate/pressrelease/oracle-java-card-boosts-security-011619.html  Gemalto https://www.gemalto.com/  Reverse engineering Java SIM card http://www.security-explorations.com/materials/javasim-reversing.pdf