Package Instance

NULL Pointer Dereference
An invalid pointer dereference on read can be triggered when an application tries to load malformed PKCS7 data with the d2i_PKCS7(), d2i_PKCS7_bio() or d2i_PKCS7_fp() functions. The result of the dereference is an application crash which could lead to a denial of service attack. The TLS implementation in OpenSSL does not call this function however third party applications might call these functions on untrusted data.

Out-of-bounds Write
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 when returning to the caller. The vulnerable code is used only
on newer PowerPC processors supporting the PowerISA 2.07 instructions.

The consequences of this kind of internal application state corruption can
be various - from no consequences, if the calling application does not
depend on the contents of non-volatile XMM registers at all, to the worst
consequences, where the attacker could get complete control of the application
process. However unless the compiler uses the vector registers for storing
pointers, the most likely consequence, if any, would be an incorrect result
of some application dependent calculations or a crash leading to a denial of
service.

The POLY1305 MAC algorithm is most frequently used as part of the
CHACHA20-POLY1305 AEAD (authenticated encryption with associated data)
algorithm. The most common usage of this AEAD cipher is with TLS protocol
versions 1.2 and 1.3. If this cipher is enabled on the server a malicious
client can influence whether this AEAD cipher is used. This implies that
TLS server applications using OpenSSL can be potentially impacted. However
we are currently not aware of any concrete application that would be affected
by this issue therefore we consider this a Low severity security issue.

Improper Certificate Validation
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.

Loop with Unreachable Exit Condition ('Infinite Loop')
Internally libssl in OpenSSL calls X509_verify_cert() on the client side to verify a certificate supplied by a server. The exact behaviour will depend on the application but it could result in crashes, infinite loops or other similar incorrect responses.