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Bug 2153471 - Backport implicit rejection for RSA PKCS#1 v1.5 encryption [rhel-9]
Summary: Backport implicit rejection for RSA PKCS#1 v1.5 encryption [rhel-9]
Alias: None
Product: Red Hat Enterprise Linux 9
Classification: Red Hat
Component: openssl
Version: 9.0
Hardware: Unspecified
OS: Unspecified
Target Milestone: rc
: ---
Assignee: Dmitry Belyavskiy
QA Contact: Hubert Kario
Mirek Jahoda
Depends On:
Blocks: CVE-2020-25659
TreeView+ depends on / blocked
Reported: 2022-12-14 16:43 UTC by Hubert Kario
Modified: 2023-11-08 08:44 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: Enhancement
Doc Text:
.OpenSSL now contains protections against Bleichenbacher-like attacks This release of the OpenSSL TLS toolkit introduces API-level protections against Bleichenbacher-like attacks on the RSA PKCS #1 v1.5 decryption process. The RSA decryption now returns a randomly generated deterministic message instead of an error if it detects an error when checking padding during a PKCS #1 v1.5 decryption. The change provides general protection against vulnerabilities such as link:https://access.redhat.com/security/cve/CVE-2020-25659[CVE-2020-25659] and link:https://access.redhat.com/security/cve/CVE-2020-25657[CVE-2020-25657]. You can disable this protection by calling the `EVP_PKEY_CTX_ctrl_str(ctx, "rsa_pkcs1_implicit_rejection". "0")` function on the RSA decryption context, but this makes your system more vulnerable.
Clone Of:
Last Closed: 2023-11-07 08:52:59 UTC
Type: Bug
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Github openssl openssl pull 13817 0 None closed Make RSA decryption API safe to use with PKCS#1 v1.5 padding 2022-12-14 16:43:34 UTC
Red Hat Issue Tracker CRYPTO-9136 0 None None None 2022-12-14 16:53:02 UTC
Red Hat Issue Tracker RHELPLAN-142266 0 None None None 2022-12-14 16:53:07 UTC
Red Hat Product Errata RHBA-2023:6627 0 None None None 2023-11-07 08:53:37 UTC

Internal Links: 2203840

Description Hubert Kario 2022-12-14 16:43:34 UTC
Description of problem:
The RSA decryption API is very easy to use incorrectly, causing issues like CVE-2020-25659 in pyca/cryptography. Please backport the recently merged implementation of implicit rejection to OpenSSL so that issues like that are properly addressed.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. Try to decrypt a malformed RSA ciphertext using PKCS#1 v1.5 padding

Actual results:
Usually, an error is returned.

Expected results:
A random, but static (for a given ciphertext-key pair) message is returned.

Additional info:

Comment 9 errata-xmlrpc 2023-11-07 08:52:59 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (openssl bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.


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