The wolfSSL embedded SSL library (formerly CyaSSL) is a lightweight SSL/TLS library written in ANSI C and targeted for embedded, RTOS, and resource-constrained environments - primarily because of its small size, speed, and feature set. It is commonly used in standard operating environments as well because of its royalty-free pricing and excellent cross platform support. wolfSSL supports industry standards up to the current TLS 1.3 and DTLS 1.3, is up to 20 times smaller than OpenSSL, and offers progressive ciphers such as ChaCha20, Curve25519, Blake2b and Post-Quantum TLS 1.3 groups. User benchmarking and feedback reports dramatically better performance when using wolfSSL over OpenSSL.
wolfSSL is powered by the wolfCrypt cryptography library. Two versions of wolfCrypt have been FIPS 140-2 validated (Certificate #2425 and certificate #3389). FIPS 140-3 validation is in progress. For additional information, visit the wolfCrypt FIPS FAQ or contact fips@wolfssl.com.
There are many reasons to choose wolfSSL as your embedded, desktop, mobile, or enterprise SSL/TLS solution. Some of the top reasons include size (typical footprint sizes range from 20-100 kB), support for the newest standards (SSL 3.0, TLS 1.0, TLS 1.1, TLS 1.2, TLS 1.3, DTLS 1.0, DTLS 1.2, and DTLS 1.3), current and progressive cipher support (including stream ciphers), multi-platform, royalty free, and an OpenSSL compatibility API to ease porting into existing applications which have previously used the OpenSSL package. For a complete feature list, see Chapter 4 of the wolfSSL manual.
wolfSSL as of 3.6.6 no longer enables SSLv3 by default. wolfSSL also no longer supports static key cipher suites with PSK, RSA, or ECDH. This means if you plan to use TLS cipher suites you must enable DH (DH is on by default), or enable ECC (ECC is on by default), or you must enable static key cipher suites with one or more of the following defines:
WOLFSSL_STATIC_DH
WOLFSSL_STATIC_RSA
WOLFSSL_STATIC_PSK
Though static key cipher suites are deprecated and will be removed from future versions of TLS. They also lower your security by removing PFS.
When compiling ssl.c
, wolfSSL will now issue a compiler error if no cipher
suites are available. You can remove this error by defining
WOLFSSL_ALLOW_NO_SUITES
in the event that you desire that, i.e., you're
not using TLS cipher suites.
wolfSSL takes a different approach to certificate verification than OpenSSL does. The default policy for the client is to verify the server, this means that if you don't load CAs to verify the server you'll get a connect error, no signer error to confirm failure (-188).
If you want to mimic OpenSSL behavior of having SSL_connect
succeed even if
verifying the server fails and reducing security you can do this by calling:
wolfSSL_CTX_set_verify(ctx, WOLFSSL_VERIFY_NONE, NULL);
before calling wolfSSL_new();
. Though it's not recommended.
The enum values SHA, SHA256, SHA384, SHA512 are no longer available when
wolfSSL is built with --enable-opensslextra
(OPENSSL_EXTRA
) or with the
macro NO_OLD_SHA_NAMES
. These names get mapped to the OpenSSL API for a
single call hash function. Instead the name WC_SHA
, WC_SHA256
, WC_SHA384
and
WC_SHA512
should be used for the enum name.
Release 5.7.2 has 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
NOTE: * --enable-heapmath is being deprecated and will be removed by end of 2024
[Medium] CVE-2024-1544 Potential ECDSA nonce side channel attack in versions of wolfSSL before 5.6.6 with wc_ecc_sign_hash calls. Generating the ECDSA nonce k samples a random number r and then truncates this randomness with a modular reduction mod n where n is the order of the elliptic curve. Analyzing the division through a control-flow revealing side-channel reveals a bias in the most significant bits of k. Depending on the curve this is either a negligible bias or a significant bias large enough to reconstruct k with lattice reduction methods. Thanks to Luca Wilke, Florian Sieck and Thomas Eisenbarth (University of Lübeck) for reporting the vulnerability. Details will appear in the proceedings of CCS 24. Fixed https://github.com/wolfSSL/wolfssl/pull/7020
[Medium] CVE-2024-5288 A private key blinding operation, enabled by defining the macro WOLFSSL_BLIND_PRIVATE_KEY, was added to mitigate a potential row hammer attack on ECC operations. If performing ECC private key operations in an environment where a malicious user could gain fine control over the device and perform row hammer style attacks it is recommended to update the version of wolfSSL used and to build with WOLFSSL_BLIND_PRIVATE_KEY defined. Thanks to Kemal Derya, M. Caner Tol, Berk Sunar for the report (Vernam Applied Cryptography and Cybersecurity Lab at Worcester Polytechnic Institute) Fixed in github pull request https://github.com/wolfSSL/wolfssl/pull/7416
[Low] When parsing a provided maliciously crafted certificate directly using wolfSSL API, outside of a TLS connection, a certificate with an excessively large number of extensions could lead to a potential DoS. There are existing sanity checks during a TLS handshake with wolfSSL which mitigate this issue. Thanks to Bing Shi for the report. Fixed in github pull request https://github.com/wolfSSL/wolfssl/pull/7597
[Low] CVE-2024-5991 In the function MatchDomainName(), input param str is treated as a NULL terminated string despite being user provided and unchecked. Specifically, the Openssl compatibility function X509_check_host() takes in a pointer and length to check against, with no requirements that it be NULL terminated. While calling without a NULL terminated string is very uncommon, it is still technically allowed. If a caller was attempting to do a name check on a non*NULL terminated buffer, the code would read beyond the bounds of the input array until it found a NULL terminator. Fixed in github pull request https://github.com/wolfSSL/wolfssl/pull/7604
[Medium] CVE-2024-5814 A malicious TLS1.2 server can force a TLS1.3 client with downgrade capability to use a ciphersuite that it did not agree to and achieve a successful connection. This is because, aside from the extensions, the client was skipping fully parsing the server hello when downgrading from TLS 1.3. Fixed in github pull request https://github.com/wolfSSL/wolfssl/pull/7619
[Medium] OCSP stapling version 2 response verification bypass issue when a crafted response of length 0 is received. Found with internal testing. Fixed in github pull request https://github.com/wolfSSL/wolfssl/pull/7702
[Medium] OCSP stapling version 2 revocation bypass with a retry of a TLS connection attempt. A revoked CA certificate could incorrectly be loaded into the trusted signers list and used in a repeat connection attempt. Found with internal testing. Fixed in github pull request https://github.com/wolfSSL/wolfssl/pull/7702
ed25519
signature is smaller than the order (PR 7513)For additional vulnerability information visit the vulnerability page at: https://www.wolfssl.com/docs/security-vulnerabilities/
See INSTALL file for build instructions. More info can be found on-line at: https://wolfssl.com/wolfSSL/Docs.html
<wolfssl_root>
├── certs [Certificates used in tests and examples]
├── cmake [Cmake build utilities]
├── debian [Debian packaging files]
├── doc [Documentation for wolfSSL (Doxygen)]
├── Docker [Prebuilt Docker environments]
├── examples [wolfSSL examples]
│ ├── asn1 [ASN.1 printing example]
│ ├── async [Asynchronous Cryptography example]
│ ├── benchmark [TLS benchmark example]
│ ├── client [Client example]
│ ├── configs [Example build configurations]
│ ├── echoclient [Echoclient example]
│ ├── echoserver [Echoserver example]
│ ├── pem [Example for convert between PEM and DER]
│ ├── sctp [Servers and clients that demonstrate wolfSSL's DTLS-SCTP support]
│ └── server [Server example]
├── IDE [Contains example projects for various development environments]
├── linuxkm [Linux Kernel Module implementation]
├── m4 [Autotools utilities]
├── mcapi [wolfSSL MPLAB X Project Files]
├── mplabx [wolfSSL MPLAB X Project Files]
├── mqx [wolfSSL Freescale CodeWarrior Project Files]
├── rpm [RPM packaging metadata]
├── RTOS
│ └── nuttx [Port of wolfSSL for NuttX]
├── scripts [Testing scripts]
├── src [wolfSSL source code]
├── sslSniffer [wolfSSL sniffer can be used to passively sniff SSL traffic]
├── support [Contains the pkg-config file]
├── tests [Unit and configuration testing]
├── testsuite [Test application that orchestrates tests]
├── tirtos [Port of wolfSSL for TI RTOS]
├── wolfcrypt [The wolfCrypt component]
│ ├── benchmark [Cryptography benchmarking application]
│ ├── src [wolfCrypt source code]
│ │ └── port [Supported hardware acceleration ports]
│ └── test [Cryptography testing application]
├── wolfssl [Header files]
│ ├── openssl [Compatibility layer headers]
│ └── wolfcrypt [Header files]
├── wrapper [wolfSSL language wrappers]
└── zephyr [Port of wolfSSL for Zephyr RTOS]