The side-channel protected T-Table implementation in wolfSSL up to version 5.6.5 protects against a side-channel attacker with cache-line resolution. In a controlled environment such as Intel SGX, an attacker can gain a per instruction sub-cache-line resolution allowing them to break the cache-line-level protection. For details on the attack refer to: https://doi.org/10.46586/tches.v2024.i1.457-500
In function MatchDomainName(), input param str is treated as a NULL terminated string despite being user provided and unchecked. Specifically, the function X509_check_host() takes in a pointer and length to check against, with no requirements that it be NULL terminated. 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.This issue affects wolfSSL: through 5.7.0.
An issue was discovered in wolfSSL before 5.7.0. A safe-error attack via Rowhammer, namely FAULT+PROBE, leads to ECDSA key disclosure. When WOLFSSL_CHECK_SIG_FAULTS is used in signing operations with private ECC keys,
such as in server-side TLS connections, the connection is halted if any fault occurs. The success rate in a certain amount of connection requests can be processed via an advanced technique for ECDSA key recovery.
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. https://doi.org/10.46586/tches.v2024.i1.457-500
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. Meaning k = r mod n. The division used
during the reduction estimates a factor q_e by dividing the upper two
digits (a digit having e.g. a size of 8 byte) of r by the upper digit of
n and then decrements q_e in a loop until it has the correct size.
Observing the number of times q_e is decremented 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. For SECP160R1, e.g., we find a bias of 15 bits.
Remotely executed SEGV and out of bounds read allows malicious packet sender to crash or cause an out of bounds read via sending a malformed packet with the correct length.
In wolfSSL prior to 5.6.6, if callback functions are enabled (via the WOLFSSL_CALLBACKS flag), then a malicious TLS client or network attacker can trigger a buffer over-read on the heap of 5 bytes (WOLFSSL_CALLBACKS is only intended for debugging).
wolfSSL prior to 5.6.6 did not check that messages in one (D)TLS record do not span key boundaries. As a result, it was possible to combine (D)TLS messages using different keys into one (D)TLS record. The most extreme edge case is that, in (D)TLS 1.3, it was possible that an unencrypted (D)TLS 1.3 record from the server containing first a ServerHello message and then the rest of the first server flight would be accepted by a wolfSSL client. In (D)TLS 1.3 the handshake is encrypted after the ServerHello but a wolfSSL client would accept an unencrypted flight from the server. This does not compromise key negotiation and authentication so it is assigned a low severity rating.
wolfSSL SP Math All RSA implementation is vulnerable to the Marvin Attack, new variation of a timing Bleichenbacher style attack, when built with the following options to configure:
--enable-all CFLAGS="-DWOLFSSL_STATIC_RSA"
The define “WOLFSSL_STATIC_RSA” enables static RSA cipher suites, which is not recommended, and has been disabled by default since wolfSSL 3.6.6. Therefore the default build since 3.6.6, even with "--enable-all", is not vulnerable to the Marvin Attack. The vulnerability is specific to static RSA cipher suites, and expected to be padding-independent.
The vulnerability allows an attacker to decrypt ciphertexts and forge signatures after probing with a large number of test observations. However the server’s private key is not exposed.
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 (Input Keying Material) 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 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. wolfSSL recommends that TLS 1.3 client side users update the version of wolfSSL used.