Stack buffer overflow in PKCS7 SignedData encoding with custom signed attributes
A stack buffer overflow vulnerability exists in wolfSSL's PKCS7 SignedData encoding functionality. In wc_PKCS7_BuildSignedAttributes(), when adding custom signed attributes, the code passes an incorrect capacity value (esd->signedAttribsCount) to EncodeAttributes() instead of the remaining available space in the fixed-size signedAttribs[7] array. When an application sets pkcs7->signedAttribsSz to a value greater than MAX_SIGNED_ATTRIBS_SZ (default 7) minus the number of default attributes already added, EncodeAttributes() writes beyond the array bounds, causing stack memory corruption. In WOLFSSL_SMALL_STACK builds, this becomes heap corrupti
Potential non-constant time compiled code with Clang LLVM
Multiple constant-time implementations in wolfSSL before version 5.8.4 may be transformed into non-constant-time binary by LLVM optimizations, which can potentially result in observable timing discrepancies and lead to information disclosure through timing side-channel attacks.
Integer Underflow Leads to Out-of-Bounds Access in XChaCha20-Poly1305 Decrypt
Integer Underflow Leads to Out-of-Bounds Access in XChaCha20-Poly1305 Decrypt. This issue is hit specifically with a call to the function wc_XChaCha20Poly1305_Decrypt() which is not used with TLS connections, only from direct calls from an application.
Constant Time Issue with Xtensa-based ESP32 and X22519
Vulnerability in X25519 constant-time cryptographic implementations due to timing side channels introduced by compiler optimizations and CPU architecture limitations, specifically with the Xtensa-based ESP32 chips. If targeting Xtensa it is recommended to use the low memory implementations of X25519, which is now turned on as the default for Xtensa.
Potential DoS Vulnerability through Multiple KeyShareEntry with Same Group in TLS 1.3 ClientHello
Improper input validation in the TLS 1.3 KeyShareEntry parsing in wolfSSL v5.8.2 on multiple platforms allows a remote unauthenticated attacker to cause a denial-of-service by sending a crafted ClientHello message containing duplicate KeyShareEntry values for the same supported group, leading to excessive CPU and memory consumption during ClientHello processing.
DoS Vulnerability in wolfSSL TLS 1.3 CKS Extension
Improper Input Validation in the TLS 1.3 CKS extension parsing in wolfSSL 5.8.2 and earlier on multiple platforms allows a remote unauthenticated attacker to potentially cause a denial-of-service via a crafted ClientHello message with duplicate CKS extensions.
Improper Validation of Signature Algorithm Used in TLS 1.3 CertificateVerify
Improper input validation in the TLS 1.3 CertificateVerify signature algorithm negotiation in wolfSSL 5.8.2 and earlier on multiple platforms allows for downgrading the signature algorithm used. For example when a client sends ECDSA P521 as the supported signature algorithm the server previously could respond as ECDSA P256 being the accepted signature algorithm and the connection would continue with using ECDSA P256, if the client supports ECDSA P256.
With TLS 1.3 pre-shared key (PSK) a malicious or faulty server could ignore the request for PFS (perfect forward secrecy) and the client would continue on with the connection using PSK without PFS. This happened when a server responded to a ClientHello containing psk_dhe_ke without a key_share extension. The re-use of an authenticated PSK connection that on the clients side unexpectedly did not have PFS, reduces the security of the connection.
In wolfSSL release 5.8.2 blinding support is turned on by default for Curve25519 in applicable builds. The blinding configure option is only for the base C implementation of Curve25519. It is not needed, or available with; ARM assembly builds, Intel assembly builds, and the small Curve25519 feature. While the side-channel attack on extracting a private key would be very difficult to execute in practice, enabling blinding provides an additional layer of protection for devices that may be more susceptible to physical access or side-channel observation.
In the OpenSSL compatibility layer implementation, the function RAND_poll() was not behaving as expected and leading to the potential for predictable values returned from RAND_bytes() after fork() is called. This can lead to weak or predictable random numbers generated in applications that are both using RAND_bytes() and doing fork() operations. This only affects applications explicitly calling RAND_bytes() after fork() and does not affect any internal TLS operations. Although RAND_bytes() documentation in OpenSSL calls out not being safe for use with fork() without first calling RAND_poll(), an additional code change was also made in wolfSSL
Domain Name Validation Bypass with Apple Native Certificate Validation
A certificate verification error in wolfSSL when building with the WOLFSSL_SYS_CA_CERTS and WOLFSSL_APPLE_NATIVE_CERT_VALIDATION options results in the wolfSSL
client failing to properly verify the server certificate's domain name,
allowing any certificate issued by a trusted CA to be accepted regardless of the hostname.
Fault Injection vulnerability in wc_ed25519_sign_msg function in wolfssl/wolfcrypt/src/ed25519.c in WolfSSL wolfssl5.6.6 on Linux/Windows allows remote attacker co-resides in the same system with a victim process to disclose information and escalate privileges via Rowhammer fault injection to the ed25519_key structure.
Fault Injection vulnerability in RsaPrivateDecryption function in wolfssl/wolfcrypt/src/rsa.c in WolfSSL wolfssl5.6.6 on Linux/Windows allows remote attacker co-resides in the same system with a victim process to disclose information and escalate privileges via Rowhammer fault injection to the RsaKey structure.
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
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 larg
Unverifed Ciphersuite used on a client-side TLS1.3 Downgrade
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
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.
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.