Timing side-channel in ECDSA signature computation
Issue summary: A timing side-channel which could potentially allow recovering
the private key exists in the ECDSA signature computation.
Impact summary: A timing side-channel in ECDSA signature computations
could allow recovering the private key by an attacker. However, measuring
the timing would require either local access to the signing application or
a very fast network connection with low latency.
There is a timing signal of around 300 nanoseconds when the top word of
the inverted ECDSA nonce value is zero. This can happen with significant
probability only for some of the supported elliptic curves. In particular
the NIST P-521 curve is
Issue summary: Calling the OpenSSL API function SSL_free_buffers may cause
memory to be accessed that was previously freed in some situations
Impact summary: A use after free can have a range of potential consequences such
as the corruption of valid data, crashes or execution of arbitrary code.
However, only applications that directly call the SSL_free_buffers function are
affected by this issue. Applications that do not call this function are not
vulnerable. Our investigations indicate that this function is rarely used by
applications.
The SSL_free_buffers function is used to free the internal OpenSSL buffer used
when processing an incomin
Low-level invalid GF(2^m) parameters lead to OOB memory access
Issue summary: Use of the low-level GF(2^m) elliptic curve APIs with untrusted
explicit values for the field polynomial can lead to out-of-bounds memory reads
or writes.
Impact summary: Out of bound memory writes can lead to an application crash or
even a possibility of a remote code execution, however, in all the protocols
involving Elliptic Curve Cryptography that we're aware of, either only "named
curves" are supported, or, if explicit curve parameters are supported, they
specify an X9.62 encoding of binary (GF(2^m)) curves that can't represent
problematic input values. Thus the likelihood of existence of a vulnerable
application is low.
Issue summary: Applications performing certificate name checks (e.g., TLS
clients checking server certificates) may attempt to read an invalid memory
address resulting in abnormal termination of the application process.
Impact summary: Abnormal termination of an application can a cause a denial of
service.
Applications performing certificate name checks (e.g., TLS clients checking
server certificates) may attempt to read an invalid memory address when
comparing the expected name with an `otherName` subject alternative name of an
X.509 certificate. This may result in an exception that terminates the
application program.
Note that basic cert
Issue summary: Calling the OpenSSL API function SSL_select_next_proto with an
empty supported client protocols buffer may cause a crash or memory contents to
be sent to the peer.
Impact summary: A buffer overread can have a range of potential consequences
such as unexpected application beahviour or a crash. In particular this issue
could result in up to 255 bytes of arbitrary private data from memory being sent
to the peer leading to a loss of confidentiality. However, only applications
that directly call the SSL_select_next_proto function with a 0 length list of
supported client protocols are affected by this issue. This would normally neve
Excessive time spent checking DSA keys and parameters
Issue summary: Checking excessively long DSA keys or parameters may be very
slow.
Impact summary: Applications that use the functions EVP_PKEY_param_check()
or EVP_PKEY_public_check() to check a DSA public key or DSA parameters may
experience long delays. Where the key or parameters that are being checked
have been obtained from an untrusted source this may lead to a Denial of
Service.
The functions EVP_PKEY_param_check() or EVP_PKEY_public_check() perform
various checks on DSA parameters. Some of those computations take a long time
if the modulus (`p` parameter) is too large.
Trying to use a very large modulus is slow and OpenSSL will not
Excessive time spent checking invalid RSA public keys
Issue summary: Checking excessively long invalid RSA public keys may take
a long time.
Impact summary: Applications that use the function EVP_PKEY_public_check()
to check RSA public keys may experience long delays. Where the key that
is being checked has been obtained from an untrusted source this may lead
to a Denial of Service.
When function EVP_PKEY_public_check() is called on RSA public keys,
a computation is done to confirm that the RSA modulus, n, is composite.
For valid RSA keys, n is a product of two or more large primes and this
computation completes quickly. However, if n is an overly large prime,
then this computation would take
Unbounded memory growth with session handling in TLSv1.3
Issue summary: Some non-default TLS server configurations can cause unbounded
memory growth when processing TLSv1.3 sessions
Impact summary: An attacker may exploit certain server configurations to trigger
unbounded memory growth that would lead to a Denial of Service
This problem can occur in TLSv1.3 if the non-default SSL_OP_NO_TICKET option is
being used (but not if early_data support is also configured and the default
anti-replay protection is in use). In this case, under certain conditions, the
session cache can get into an incorrect state and it will fail to flush properly
as it fills. The session cache will continue to grow in an unb
Issue summary: Processing a maliciously formatted PKCS12 file may lead OpenSSL
to crash leading to a potential Denial of Service attack
Impact summary: Applications loading files in the PKCS12 format from untrusted
sources might terminate abruptly.
A file in PKCS12 format can contain certificates and keys and may come from an
untrusted source. The PKCS12 specification allows certain fields to be NULL, but
OpenSSL does not correctly check for this case. This can lead to a NULL pointer
dereference that results in OpenSSL crashing. If an application processes PKCS12
files from an untrusted source using the OpenSSL APIs then that application wi
POLY1305 MAC implementation corrupts vector registers on PowerPC
Issue summary: The POLY1305 MAC (message authentication code) implementation
contains a bug that might corrupt the internal state of applications running
on PowerPC CPU based platforms if the CPU provides vector instructions.
Impact summary: If an attacker can influence whether the POLY1305 MAC
algorithm is used, the application state might be corrupted with various
application dependent consequences.
The POLY1305 MAC (message authentication code) implementation in OpenSSL for
PowerPC CPUs restores the contents of vector registers in a different order
than they are saved. Thus the contents of some of these vector registers
are corrupted whe
Excessive time spent in DH check / generation with large Q parameter value
Issue summary: Generating excessively long X9.42 DH keys or checking
excessively long X9.42 DH keys or parameters may be very slow.
Impact summary: Applications that use the functions DH_generate_key() to
generate an X9.42 DH key may experience long delays. Likewise, applications
that use DH_check_pub_key(), DH_check_pub_key_ex() or EVP_PKEY_public_check()
to check an X9.42 DH key or X9.42 DH parameters may experience long delays.
Where the key or parameters that are being checked have been obtained from
an untrusted source this may lead to a Denial of Service.
While DH_check() performs all the necessary checks (as of CVE-2023-3817),
DH_ch
Issue summary: A bug has been identified in the processing of key and
initialisation vector (IV) lengths. This can lead to potential truncation
or overruns during the initialisation of some symmetric ciphers.
Impact summary: A truncation in the IV can result in non-uniqueness,
which could result in loss of confidentiality for some cipher modes.
When calling EVP_EncryptInit_ex2(), EVP_DecryptInit_ex2() or
EVP_CipherInit_ex2() the provided OSSL_PARAM array is processed after
the key and IV have been established. Any alterations to the key length,
via the "keylen" parameter or the IV length, via the "ivlen" parameter,
within the OSSL_PARAM a
Excessive time spent checking DH q parameter value
Issue summary: Checking excessively long DH keys or parameters may be very slow.
Impact summary: Applications that use the functions DH_check(), DH_check_ex()
or EVP_PKEY_param_check() to check a DH key or DH parameters may experience long
delays. Where the key or parameters that are being checked have been obtained
from an untrusted source this may lead to a Denial of Service.
The function DH_check() performs various checks on DH parameters. After fixing
CVE-2023-3446 it was discovered that a large q parameter value can also trigger
an overly long computation during some of these checks. A correct q value,
if present, cannot be larger than
Excessive time spent checking DH keys and parameters
Issue summary: Checking excessively long DH keys or parameters may be very slow.
Impact summary: Applications that use the functions DH_check(), DH_check_ex()
or EVP_PKEY_param_check() to check a DH key or DH parameters may experience long
delays. Where the key or parameters that are being checked have been obtained
from an untrusted source this may lead to a Denial of Service.
The function DH_check() performs various checks on DH parameters. One of those
checks confirms that the modulus ('p' parameter) is not too large. Trying to use
a very large modulus is slow and OpenSSL will not normally use a modulus which
is over 10,000 bits in lengt
AES-SIV implementation ignores empty associated data entries
Issue summary: The AES-SIV cipher implementation contains a bug that causes
it to ignore empty associated data entries which are unauthenticated as
a consequence.
Impact summary: Applications that use the AES-SIV algorithm and want to
authenticate empty data entries as associated data can be misled by removing,
adding or reordering such empty entries as these are ignored by the OpenSSL
implementation. We are currently unaware of any such applications.
The AES-SIV algorithm allows for authentication of multiple associated
data entries along with the encryption. To authenticate empty data the
application has to call EVP_EncryptUpdate() (or EV
Issue summary: Processing some specially crafted ASN.1 object identifiers or
data containing them may be very slow.
Impact summary: Applications that use OBJ_obj2txt() directly, or use any of
the OpenSSL subsystems OCSP, PKCS7/SMIME, CMS, CMP/CRMF or TS with no message
size limit may experience notable to very long delays when processing those
messages, which may lead to a Denial of Service.
An OBJECT IDENTIFIER is composed of a series of numbers - sub-identifiers -
most of which have no size limit. OBJ_obj2txt() may be used to translate
an ASN.1 OBJECT IDENTIFIER given in DER encoding form (using the OpenSSL
type ASN1_OBJECT) to its canon
Input buffer over-read in AES-XTS implementation on 64 bit ARM
Issue summary: The AES-XTS cipher decryption implementation for 64 bit ARM
platform contains a bug that could cause it to read past the input buffer,
leading to a crash.
Impact summary: Applications that use the AES-XTS algorithm on the 64 bit ARM
platform can crash in rare circumstances. The AES-XTS algorithm is usually
used for disk encryption.
The AES-XTS cipher decryption implementation for 64 bit ARM platform will read
past the end of the ciphertext buffer if the ciphertext size is 4 mod 5 in 16
byte blocks, e.g. 144 bytes or 1024 bytes. If the memory after the ciphertext
buffer is unmapped, this will trigger a crash which results in a
The function X509_VERIFY_PARAM_add0_policy() is documented to
implicitly enable the certificate policy check when doing certificate
verification. However the implementation of the function does not
enable the check which allows certificates with invalid or incorrect
policies to pass the certificate verification.
As suddenly enabling the policy check could break existing deployments it was
decided to keep the existing behavior of the X509_VERIFY_PARAM_add0_policy()
function.
Instead the applications that require OpenSSL to perform certificate
policy check need to use X509_VERIFY_PARAM_set1_policies() or explicitly
enable the policy check by