wolfSSL release 5.6.2 and 5.6.3 contained 6 vulnerability fixes. The listed issues were found by external researchers (thanks to their efforts! you can see them mentioned on each of the reports).
- In cases where a malicious agent could analyze cache timing at a very detailed level, information about the AES key used could be leaked during T/S Box lookups. One such case was shown on RISC-V hardware using the MicroWalk tool (https://github.com/microwalk-project/Microwalk). A hardened version of T/S Box lookups was added in wolfSSL to help mitigate this potential attack and is now on by default with RISC-V builds and can be enabled on other builds if desired by compiling wolfSSL with the macro WOLFSSL_AES_TOUCH_LINES. Thanks to Jan Wichelmann, Christopher Peredy, Florian Sieck, Anna Pätschke, Thomas Eisenbarth (University of Lübeck): MAMBO-V: Dynamic Side-Channel Leakage Analysis on RISC-V. Fixed in the following GitHub pull request #6309
- In previous versions of wolfSSL if a TLS 1.3 client gets neither a PSK (pre shared key) extension nor a KSE (key share extension) when connecting to a malicious server, a default predictable buffer gets used for the IKM value when generating the session master secret. Using a potentially known IKM value when generating the session master secret key compromises the key generated, allowing an eavesdropper to reconstruct it and potentially allowing surreptitious access to or meddling with message contents in the session. This issue does not affect client validation of connected servers, nor expose private key information, but could result in an insecure TLS 1.3 session when not controlling both sides of the connection. We recommend that TLS 1.3 client side users update the version of wolfSSL used. Thanks to Johannes from Sectra Communications and Linköping University for the report. Fixed in the following GitHub pull request #6412
- Fix for setting the atomic macro options introduced in release 5.6.2. This issue affects GNU gcc autoconf builds. The fix resolves a potential mismatch of the generated macros defined in options.h file and the macros used when the wolfSSL library is compiled. In version 5.6.2 this mismatch could result in unstable runtime behavior.
- Fix for invalid suffix error with Windows build using the macro GCM_TABLE_4BIT.
- Improvements to Encrypted Memory support (WC_PROTECT_ENCRYPTED_MEM) implementations for modular exponentiation in SP math-all (sp_int.c) and TFM (tfm.c).
- Improvements to SendAlert for getting output buffer.
Release 5.6.2 and 5.6.3 have been developed according to wolfSSL’s development and QA process (see link below) and successfully passed the quality criteria.
https://www.wolfssl.com/about/wolfssl-software-development-process-quality-assurance
If you have questions on any of the above, please contact us at facts@wolfssl.com, or call us at +1 425 245 8247.