BUSted: Side-channel attacks to TrustZone-M separation
Recent research from Universidade do Minho in Portugal was presented at the Black Hat Asia conference in Singapore. The work of Dr. Sandro Pinto and Cristiano Rodrigues brought to the surface a groundbreaking technique that exploits the shared pipeline on the newest Cortex-M CPUs to place a time based, side-channel attack from an application running in non-secure domain to security code running in secure mode. The researchers named this attack “BUSted”. This is sudden and difficult news hitting the new generations of ARMv8 microcontrollers. The attack was demonstrated live using a Cortex-M33 microcontroller as target.
Due to the nature of the attack, targeting specific microarchitectural design issues, this disclosure has already been compared to “Spectre” and “Meltdown”, well known attacks that have affected more sophisticated architectures in the recent past. All the embedded projects that were counting on hardware-assisted privilege separation through TrustZone-M should now take into account the possibility of leaking information from the trusted components running in the secure world.
According to the researchers, software based countermeasures and mitigations are possible to counter the effects of this microarchitectural design fault. The most important aspect to take into account when dealing with time-based attacks is to avoid as much as possible secret-dependent code in the implementation of security operations. In other words, the time required for a security procedure to run must not depend on the success of the operation or on any secret involved in the operation.
wolfCrypt cryptography functions are already secret-independent. Our implementation ensures that all the critical operations that involve secrets are run in constant-time, unless specifically disabled. When using wolfSSL software, you should expect these types of countermeasures to be activated by default. This specific attack however may be even more subtle, because it can target custom code built around hardened code, e.g. if wolfCrypt cryptography is accessed through a custom wrapper in non-secure-callable code. In this case even the smallest time difference between two branches of a single ‘if’ instruction may be sufficient to make assumptions on the results of the underlying secure operation or on any of the keys. As the authors of the research suggest, there might be additional specific mitigations needed.
Our secure bootloader, wolfBoot, is capable of configuring and managing the separation between the two execution domains on Cortex-M23, M33 and M35 targets. In future releases wolfBoot will also feature a secure domain monitor that handles cross-domain calls from the application, protecting cryptography code and keys from direct access from the non-secure world.
wolfBoot’s main responsibility is of course to secure the boot process by ensuring that no unauthorized application code can execute in the non-secure domain. Our recommendation is to always enforce public-key based authentication of all the software running on the system, to cut the origin of these attacks as much as possible, by preventing rogue code to be run on the system. By using wolfcrypt, all the necessary mitigations against side-channel attacks are already integrated and activated by default.
You can download wolfBoot today from our download page or from our github repository
Has your design been affected by “BUSted”? Is your embedded system currently relying on TEE to enforce privilege separation between software modules? Share your story with us and let us know. Ask us anything about time-based attacks, hardened code and side-channel prevention! If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.
AWS wolfMQTT client support for MQTT v5.0
Around the end of last year, Amazon announced MQTT v5.0 support for its AWS IoT Core MQTT Broker. Support for this protocol was added to the AWS wolfMQTT client example with a recent effort here at wolfSSL.
The wolfMQTT library is a client implementation of MQTT written in C for embedded use, with support for SSL/TLS via the wolfSSL library. wolfMQTT supports both the MQTT 3.1.1 specification as well as the MQTT v5.0 specification. And with the recent updates, the AWS client can now be used to test out AWS IoT Core’s new protocol support and its functionality. Note that we updated our AWS host instance to use an ATS endpoint, as they are the only ones that support MQTT v5.0 as of now.
For more information about wolfMQTT or its MQTT v5.0 support, If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.
Reference
wolfMQTT GitHub Repository
wolfMQTT User Manual
AWS MQTT v5.0 Upgrade
AWS IoT Core ATS
MQTT v5.0 specification
HiveMQ: “MQTT 5: Upgrade now. Here’s why.”
wolfSSL at Xponential 2023
WolfSSL will attend Xponential at booth 3014 May 9th to May 11th in Denver, CO. At Xponential 2023, the focus is on new developments in unmanned vehicle systems.
WolfSSL offers highly optimized TLS and cryptography libraries that secure IoT devices and embedded systems against cyber attacks. At both tradeshows, the wolfSSL team will meet with attendees and discuss how their products can support their projects. They have the expertise and experience to help you achieve your security goals and enhance system performance.
By scheduling a meeting with the wolfSSL team attendees can gain valuable insights into the latest trends and technologies in cybersecurity. Don’t miss out on this opportunity to meet with wolfSSL and explore the latest advancements in unmanned vehicle security.
If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.
wolfSSL Inc: Latest news on FIPS cert #3389
wolfSSL is extremely proud to announce that an additional 18 OEs (Operating Environments) have been added to cert #3389 with only a 62-day turnaround from the CMVP between submission and approval: Feb 23 2023 – April 26 2023.
INFO:
Cert Location: https://csrc.nist.gov/projects/cryptographic-module-validation-program/certificate/3389
SunSet Date: 3/3/2024
Operating Environments validated (raw count): 73
Operating Environments validated (non-PAA specific): 50
The 18 OEs that were added to cert #3389 are as follows:
- Linux 3.10 (CentOS 7) Intel® Atom™ CPU D525 @ 1.80GHz with PAA Beckman Coulter PROService RAP BOX 4.3.2
- Linux 3.10 (CentOS 7) Intel® Atom™ CPU D525 @ 1.80GHz without PAA Beckman Coulter PROService RAP BOX 4.3.2
- Yocto (dunfell) 3.1 AMD GX-412TC SoC with PAA LinkGuard 4.3.2
- Yocto (dunfell) 3.1 AMD GX-412TC SoC without PAA LinkGuard 4.3.2
- Linux 5.4 Intel® Xeon® Gold 5218 CPU @ 2.30GHz LiveAction LiveNX Appliance 4.3.2
- Windows 10 Pro Intel® Core™ i7-1255U @ 1.70 Ghz Dell Precision 3570 4.3.2
- Debian GNU/Linux 8 (jessie) Intel® Atom™ C2558 @ 2.40GHz ufiSpace Cloud and Data Center Switch S7810-54QS 4.3.2a
- FreeBSD 10.3 on VMWare ESXi 7.0 Intel® Xeon® Silver 4210 @ 2.20GHz Supermicro X11DPH-i 4.3.2a
- Linux 5.15 on VMWare ESXi 7.0 Intel® Xeon® Silver 4210 @ 2.20GHz Supermicro X11DPH-i 4.3.2a
- Debian GNU/Linux 8 (jessie) Broadcom BCM5634 Corning 1LAN-SDDP24POE 4.3.2a
- Linux IPHO00550F22 4.1 Broadcom BCM6858 Corning 1LAN-SDAN-7691 4.3.2a
- Linux IPHO00559B23 3.4 Broadcom BCM6838 Corning 1LAN-SDAN-7290 4.3.2a
- macOS Monterey 12.5 Intel® Core™ i7-8569U @ 2.80Ghz with PAA Macbook Pro 4.3.2a
- Windows 11 Enterprise Intel® Core™ i7-10610U @ 1.80Ghz with PAA Dell Latitude 7410 4.3.2a
- macOS Monterey 12.5 Apple M1 Max with PAA Macbook Pro 4.5.4a
- VxWorks 7 SR0630 Intel® Core™ i7-5850EQ @ 2.70GHz F-16 WASP 4.3.2a
- macOS Monterey 12.5 Apple M1 with PAA Macbook Air 4.5.4b
- macOS Monterey 12.5 Apple M1 without PAA Macbook Air 4.5.4b
This brings the total count of OEs tested and validated by wolfSSL Inc (vendor) in collaboration with UL Verification Services Inc (NVLAP accredited FIPS lab) under cert #3389 to a whopping total of 77! 4 OEs that had originally been tested and validated prior to SP800-56A Rev3 requirements were dropped from cert #3389 during the retesting effort leaving a total of 73 tested and validated Operating Environments under FIPS certificate #3389.
For a full list of all 73 tested and validated Operating Environments please checkout FIPS cert #3389 using the link to the certificate at the top of this blog post. If you have any questions about adding an OE please contact wolfSSL at fips@wolfssl.com anytime.
NEWS and the future of FIPS at wolfSSL and cert 3389:
As we approach the SunSet date of cert #3389, which is coming in March of 2024, wolfSSL would like to take this opportunity to address a few topics that regularly come up regarding impact of current and future projects.
- Once a certificate is moved to the historical list a banner is placed at the top of that cert that states: “Historical – The referenced cryptographic module should not be included by Federal Agencies in new procurements. Agencies may make a risk determination on whether to continue using this module based on their own assessment of where and how it is used.“
- This means the certificate is unlikely to be acceptable for NEW contracts/projects, and can sometimes also impact ongoing software/firmware updates on previously closed contracts/projects. It is up to the purchase authority to weigh the RISK of using older FIPS certificates prior to making an acquisition for a project involving a FIPS requirement.
- It is not unheard of that already fielded products may continue to ship software/firmware updates under a historical certificate.
- To that end wolfSSL will continue to maintain, test and support cert #3389 FIPS modules long after cert #3389 is moved to the historical list on behalf of any customers still dependent upon it.
- Those customers looking to close on NEW contracts/projects with a FIPS requirement will be happy to hear that wolfSSL Inc was one of the first 20 vendors in the world to be in process for FIPS 140-3 and estimates are that the wolfCrypt module is currently #16 in the CMVP queue for receiving a FIPS 140-3 certificate.
- To-date only 3 vendors (Apple, AMD and VMware) have received 140-3 certificates none of which are commercial FIPS module offerings. wolfSSL anticipates being one of the first (if not THE first) commercial FIPS offering in the world for FIPS 140-3!
- Cert #3389 can not be extended beyond March of 2024 unless the CMVP decides to change their extension policies regarding FIPS 140-2 given that FIPS 140-3 modules are taking SO long to be approved.
- wolfSSL Inc feels the likelihood of such an extension policy change is small however the probability does exist and is worth mentioning
- wolfSSL is seeing great demand from the industry for 140-3 as soon as it is available. wolfSSL Inc anticipates adding 25 (or more) OEs in the first year after receiving 140-3 certification for the wolfCrypt module. This means there may be a delay if one hesitates too long, please start planning FIPS projects today and get wolfSSL hardware ASAP to have an OE validated under the wolfSSL Inc 140-3 certificate once it is issued!
Are you interested in FIPS? If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.
wolfSSL Embraces ASCON Lightweight Cryptography
The cryptography world is abuzz with the new proposed NIST standard, Ascon. Earlier this year, NIST selected the Ascon family “for lightweight cryptography applications as it meets the needs of most use cases where lightweight cryptography is required”. More details can be found at the NIST News Update. We at wolfSSL have been testing an initial prototype to have this suite ready for production release as soon as the standard is finalized.
Like all serious, commercial-grade cryptography software, the Ascon implementation is completely open source. Each of the candidate authors has signed a release.
The Ascon suite contains these 12 algorithms:
- crypto_aead/ascon128v12: Ascon-128
- crypto_aead/ascon128av12: Ascon-128a
- crypto_aead/ascon80pqv12: Ascon-80pq
- crypto_hash/asconhashv12: Ascon-Hash
- crypto_hash/asconhashav12: Ascon-Hasha
- crypto_hash/asconxofv12: Ascon-Xof
- crypto_hash/asconxofav12: Ascon-Xofa
- crypto_auth/asconmacv12: Ascon-Mac
- crypto_auth/asconprfv12: Ascon-Prf
- crypto_auth/asconprfsv12: Ascon-PrfShort
For the full details of the implementation, see: https://ascon.iaik.tugraz.at/files/asconv12-nist.pdf
Part of the requirements of the new lightweight crypto was to be easily implemented in hardware. Of particular interest to hardware implementers is the RTL VHDL source code.
Embedded developers in particular will be very interested in these new algorithms designed specifically to be used on small devices with limited memory and computational resources. Are you an embedded developer? Are you interested in ASCON for your project? If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.
OpenSSL 1.1.1 EOL
Have you heard the news from the OpenSSL blog? If you are using the 1.1.1 branch of releases of OpenSSL, come September 11, 2023, there will be no more updates. You can get the details here:
https://www.openssl.org/blog/blog/2023/03/28/1.1.1-EOL/
That said, you can breathe a sigh of relief because wolfSSL is here to help. We have three ways to help.
Compatibility Layer
During the configure step of building wolfSSL, simply use –enable-opensslall and that will turn on our compatibility layer. Your application build will then have to point to wolfSSL’s include path and binary library file. You should not need to change your source code. That said, if you find you are getting build errors about missing APIs, please send a message to support@wolfssl.com. We would love to help you keep your code base as clean and simple as possible.
wolfEngine
There are some cases where the compatibility layer might not be appropriate. For example, you might be directly modifying members of OpenSSL’s structures since not all of them are hidden. For such cases, we have wolfEngine. You can continue using OpenSSL, but under the hood the wolfCrypt implementations of the cryptographic algorithms will be used. This might be especially useful if you are looking for an accelerated path to FIPS certification.
wolfProvider
Perhaps you have already gone through the work of migrating to the OpenSSL 3.0.x branches. Noticing any performance issues? Having trouble finding help or getting support? The wolfSSL team is known for having the fastest cryptographic implementations and providing excellent support. Why not try out wolfProvider to see if it can help your project? Like wolfEngine, if you are looking for an accelerated path to FIPS certification, this might be your solution.No matter your circumstances, we are here to help you through this trying time as OpenSSL ends support for the 1.1.1 series of releases. If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.
Free wolfSSL Training Course (April 19th & 20th)
If you’re interested in learning more about SSL/TLS or the wolfSSL lightweight SSL library, then you’re in luck. wolfSSL is offering a free 2-day (4 hours each day) training course on wolfSSL.
The next instance of this training course will take place April 19th & 20th from 12:00 PM to 5:00 PM (UTC) both days. This instance was scheduled to accommodate European timezones, soon we will announce an instance that will accommodate Asia time zones.
The course includes Q&A sessions throughout the webinar. To get full access to the course, participants must register for both days. If you’re interested in learning more about SSL/TLS or the wolfSSL library, this training course is an excellent opportunity to deepen your knowledge and skills in this area.
Watch the webinar here: wolfSSL Training Part 1 , wolfSSL Training Part 2
The course objectives are to provide attendees with a basic understanding of how SSL/TLS work, learn the package and design of wolfSSL, effectively build wolfSSL for target platforms, learn effective wolfSSL debugging strategies, add wolfSSL to different client and server applications, learn best practices for adding wolfSSL to embedded, desktop/enterprise, or cloud applications or devices, and develop using wolfSSL’s underlying cryptography library.
If you are working towards CISSP (Certified Information Systems Security Professional) certificate this training webinar could qualify for Group A Credits as a domain related activity. If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.
DTLS 1.2 and 1.3 Stateless ClientHello Parsing
wolfSSL implements support for both client side and server side DTLS. The server side requires extra attention when it comes to Denial-of-Service (DoS) attacks. One way to mitigate DoS on DTLS servers is to operate statelessly until a cookie exchange is completed with the peer. The cookie exchange is implemented in all versions of DTLS. DTLS 1.2 uses a special HelloVerifyRequest message while DTLS 1.3 uses the TLS 1.3 HelloRetryRequest with a cookie extension. The general principle of the cookie exchange is shown in the following figures.
Client Server
------ ------
ClientHello ------>
<----- HelloVerifyRequest
(contains cookie)
ClientHello ------>
(with cookie)
[Rest of handshake]
Figure 1: DTLS 1.2 cookie exchange (https://www.rfc-editor.org/rfc/rfc6347#section-4.2.1)
Client Server
------ ------
ClientHello ------>
<----- HelloRetryRequest
+ cookie
ClientHello ------>
+ cookie
[Rest of handshake]
Figure 2: DTLS 1.3 cookie exchange (https://www.rfc-editor.org/rfc/rfc9147.html#section-5.1)
The trick is to parse the initial ClientHello without maintaining state. In wolfSSL release 5.6.0, we implemented parsing the initial ClientHello without maintaining state at all (https://github.com/wolfSSL/wolfssl/pull/5910). Previously, wolfSSL would reset the object when requesting a cookie exchange but this can be unreliable on errors or when new features are implemented. Now we have a dedicated routine to parse the ClientHello statelessly.
wolfSSL also has a callback available when a peer has been verified. To set this callback, use the int wolfDTLS_SetChGoodCb(WOLFSSL* ssl, ClientHelloGoodCb cb, void* user_ctx) API.
If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.
wolfSSH Release v1.4.13
wolfSSL Inc is proud to announce an important incremental update to wolfSSH: v1.4.13!
In this release, we fix a severe user authentication bug in wolfSSHd. It is highly recommended that anyone using wolfSSHd upgrade to this version immediately (see Vulnerabilities in the change log below).
We have added a STM32Cube Expansion Pack for building in that environment. The daemonization and test coverage of wolfSSHd has been improved. We also improved support for transferring large files with SFTP. We also have a testbed for checking wolfSSH with LwIP using both FreeRTOS and Linux.
The release information from the change log is reposted below:
wolfSSH v1.4.13 (Apr 3, 2023)
New Feature Additions and Improvements
- Improvement to forking the wolfSSHd daemon.
- Added an STM32Cube Expansion pack. See the file _ide/STM32CUBE/README.md_ for more information. (https://www.wolfssl.com/files/ide/I-CUBE-wolfSSH.pack)
- Improved test coverage for wolfSSHd.
- X.509 style private key support.
Fixes
- Fixed shadow password checking in wolfSSHd.
- Building cleanups: warnings, types, 32-bit.
- SFTP fixes for large files.
- Testing and fixes with SFTP and LwIP.
Vulnerabilities
- wolfSSHd would allow users without passwords to log in with any password. This is fixed as of this version. The return value of crypt() was not correctly checked. This issue was introduced in v1.4.11 and only affects wolfSSHd when using the default authentication callback provided with wolfSSHd. Anyone using wolfSSHd should upgrade to v1.4.13.
If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.
wolfSSH STM32Cube Expansion Package for STM32 is now available!
wolfSSH offers all the functionality of a SSH server and client in a compact and microcontroller friendly library and is now available for use as an STM32Cube Package. wolfCrypt, the crypto engine for wolfSSH, heavily supports STM32 hardware and now you can leverage wolfSSH as an SSH solution in the same environment. wolfSSH supports SSH protocol v.2 with both password and public key based authentication and is the easiest way to implement SFTP and SCP on embedded targets, giving the possibility to customize the actions associated with remote filesystem access operations.
Download the new STM32Cube Pack from https://www.wolfssl.com/files/ide/I-CUBE-wolfSSH.pack and follow the documentation here to get started.
You can also reference this webinar for more insight on running wolfSSL on STM32 hardware. How to use wolfSSL software expansion for STM32Cube
If you have any questions or run into any issues, contact us at facts@wolfssl.com, or call us at +1 425 245 8247.