ALAS2023-2023-181


Amazon Linux 2023 Security Advisory: ALAS-2023-181
Advisory Release Date: 2023-05-11 17:49 Pacific
Advisory Updated Date: 2023-05-24 18:56 Pacific
Severity: Medium

Issue Overview:

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. (CVE-2023-0464)

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. (CVE-2023-0465)

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. (CVE-2023-0466)

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. (CVE-2023-1255)


Affected Packages:

openssl


Issue Correction:
Run dnf update openssl --releasever 2023.0.20230517 to update your system.

New Packages:
aarch64:
    openssl-libs-debuginfo-3.0.8-1.amzn2023.0.2.aarch64
    openssl-debuginfo-3.0.8-1.amzn2023.0.2.aarch64
    openssl-perl-3.0.8-1.amzn2023.0.2.aarch64
    openssl-libs-3.0.8-1.amzn2023.0.2.aarch64
    openssl-3.0.8-1.amzn2023.0.2.aarch64
    openssl-debugsource-3.0.8-1.amzn2023.0.2.aarch64
    openssl-devel-3.0.8-1.amzn2023.0.2.aarch64

src:
    openssl-3.0.8-1.amzn2023.0.2.src

x86_64:
    openssl-libs-debuginfo-3.0.8-1.amzn2023.0.2.x86_64
    openssl-perl-3.0.8-1.amzn2023.0.2.x86_64
    openssl-debuginfo-3.0.8-1.amzn2023.0.2.x86_64
    openssl-libs-3.0.8-1.amzn2023.0.2.x86_64
    openssl-debugsource-3.0.8-1.amzn2023.0.2.x86_64
    openssl-3.0.8-1.amzn2023.0.2.x86_64
    openssl-devel-3.0.8-1.amzn2023.0.2.x86_64