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 the modulus p parameter, thus it is
unnecessary to perform these checks if q is larger than p.
An application that calls DH_check() and supplies a key or parameters obtained
from an untrusted source could be vulnerable to a Denial of Service attack.
The function DH_check() is itself called by a number of other OpenSSL functions.
An application calling any of those other functions may similarly be affected.
The other functions affected by this are DH_check_ex() and
EVP_PKEY_param_check().
Also vulnerable are the OpenSSL dhparam and pkeyparam command line applications
when using the "-check" option.
The OpenSSL SSL/TLS implementation is not affected by this issue.
The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.
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 EVP_CipherUpdate()) with
NULL pointer as the output buffer and 0 as the input buffer length.
The AES-SIV implementation in OpenSSL just returns success for such a call
instead of performing the associated data authentication operation.
The empty data thus will not be authenticated.
As this issue does not affect non-empty associated data authentication and
we expect it to be rare for an application to use empty associated data
entries this is qualified as Low severity issue.
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 canonical numeric text form, which are the
sub-identifiers of the OBJECT IDENTIFIER in decimal form, separated by
periods.
When one of the sub-identifiers in the OBJECT IDENTIFIER is very large
(these are sizes that are seen as absurdly large, taking up tens or hundreds
of KiBs), the translation to a decimal number in text may take a very long
time. The time complexity is O(n^2) with 'n' being the size of the
sub-identifiers in bytes (*).
With OpenSSL 3.0, support to fetch cryptographic algorithms using names /
identifiers in string form was introduced. This includes using OBJECT
IDENTIFIERs in canonical numeric text form as identifiers for fetching
algorithms.
Such OBJECT IDENTIFIERs may be received through the ASN.1 structure
AlgorithmIdentifier, which is commonly used in multiple protocols to specify
what cryptographic algorithm should be used to sign or verify, encrypt or
decrypt, or digest passed data.
Applications that call OBJ_obj2txt() directly with untrusted data are
affected, with any version of OpenSSL. If the use is for the mere purpose
of display, the severity is considered low.
In OpenSSL 3.0 and newer, this affects the subsystems OCSP, PKCS7/SMIME,
CMS, CMP/CRMF or TS. It also impacts anything that processes X.509
certificates, including simple things like verifying its signature.
The impact on TLS is relatively low, because all versions of OpenSSL have a
100KiB limit on the peer's certificate chain. Additionally, this only
impacts clients, or servers that have explicitly enabled client
authentication.
In OpenSSL 1.1.1 and 1.0.2, this only affects displaying diverse objects,
such as X.509 certificates. This is assumed to not happen in such a way
that it would cause a Denial of Service, so these versions are considered
not affected by this issue in such a way that it would be cause for concern,
and the severity is therefore considered low.
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 denial of
service.
If an attacker can control the size and location of the ciphertext buffer
being decrypted by an application using AES-XTS on 64 bit ARM, the
application is affected. This is fairly unlikely making this issue
a Low severity one.
Applications that use a non-default option when verifying certificates may be
vulnerable to an attack from a malicious CA to circumvent certain checks.
Invalid certificate policies in leaf certificates are silently ignored by
OpenSSL and other certificate policy checks are skipped for that certificate.
A malicious CA could use this to deliberately assert invalid certificate policies
in order to circumvent policy checking on the certificate altogether.
Policy processing is disabled by default but can be enabled by passing
the `-policy' argument to the command line utilities or by calling the
`X509_VERIFY_PARAM_set1_policies()' function.
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 calling X509_VERIFY_PARAM_set_flags() with
the X509_V_FLAG_POLICY_CHECK flag argument.
Certificate policy checks are disabled by default in OpenSSL and are not
commonly used by applications.
A security vulnerability has been identified in all supported versions
of OpenSSL related to the verification of X.509 certificate chains
that include policy constraints. Attackers may be able to exploit this
vulnerability by creating a malicious certificate chain that triggers
exponential use of computational resources, leading to a denial-of-service
(DoS) attack on affected systems.
Policy processing is disabled by default but can be enabled by passing
the `-policy' argument to the command line utilities or by calling the
`X509_VERIFY_PARAM_set1_policies()' function.
A bug exists in the way mod_ssl handled client renegotiations. A remote attacker could send a carefully crafted request that would cause mod_ssl to enter a loop leading to a denial of service. This bug can be only triggered with Apache HTTP Server version 2.4.37 when using OpenSSL version 1.1.1 or later, due to an interaction in changes to handling of renegotiation attempts.
mutt_ssl.c in mutt 1.5.19 and 1.5.20, when OpenSSL is used, does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.
mutt_ssl.c in mutt 1.5.16 and other versions before 1.5.19, when OpenSSL is used, does not verify the domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.