OpenSSL vulnerability
CVE-2022-3602 (Remote Code Execution) and CVE-2022-3786 (Denial of Service)

November 4, 2022November 4, 2022 oitjh hacking, intelligence, ssl

What is OpenSSL?

Open SSL is an all-around cryptography library that offers an open-source application of the TLS protocol. First released in 1998, it is available for Linux, Windows, macOS, and BSD systems. OpenSSL allows users to perform various SSL-related tasks, including CSR (Certificate Signing Request) and private keys generation, and SSL certificate installation.

Most of the Linux distributions come with OpenSSL pre-compiled, but if you’re on a Windows system, you can get it from here.

Check your OpenSSL version

It’s imperative to know what OpenSSL version you have as it determines which cryptographic algorithms and protocols you can use. The latest OpenSSL release is 3.0.0. It supports the TLS 1.3 protocol and restores FIPS 140 support.

You can check your OpenSSL version by running the following command:

openssl version –a

OpenSSL Security Advisory [01 November 2022]

OpenSSL Security Advisory [01 November 2022]
============================================

X.509 Email Address 4-byte Buffer Overflow (CVE-2022-3602)
==========================================================

Severity: High

A buffer overrun can be triggered in X.509 certificate verification,
specifically in name constraint checking. Note that this occurs
after certificate chain signature verification and requires either a
CA to have signed the malicious certificate or for the application to
continue certificate verification despite failure to construct a path
to a trusted issuer. An attacker can craft a malicious email address
to overflow four attacker-controlled bytes on the stack. This buffer
overflow could result in a crash (causing a denial of service) or
potentially remote code execution.

Many platforms implement stack overflow protections which would mitigate
against the risk of remote code execution. The risk may be further
mitigated based on stack layout for any given platform/compiler.

Pre-announcements of CVE-2022-3602 described this issue as CRITICAL.
Further analysis based on some of the mitigating factors described above
have led this to be downgraded to HIGH. Users are still encouraged to
upgrade to a new version as soon as possible.

In a TLS client, this can be triggered by connecting to a malicious
server. In a TLS server, this can be triggered if the server requests
client authentication and a malicious client connects.

OpenSSL versions 3.0.0 to 3.0.6 are vulnerable to this issue.

OpenSSL 3.0 users should upgrade to OpenSSL 3.0.7.

OpenSSL 1.1.1 and 1.0.2 are not affected by this issue.

This issue was reported to OpenSSL on 17th October 2022 by Polar Bear.
The fixes were developed by Dr Paul Dale.

We are not aware of any working exploit that could lead to code execution,
and we have no evidence of this issue being exploited as of the time of
release of this advisory (November 1st 2022).

X.509 Email Address Variable Length Buffer Overflow (CVE-2022-3786)
===================================================================

Severity: High

A buffer overrun can be triggered in X.509 certificate verification,
specifically in name constraint checking. Note that this occurs after
certificate chain signature verification and requires either a CA to
have signed a malicious certificate or for an application to continue
certificate verification despite failure to construct a path to a trusted
issuer. An attacker can craft a malicious email address in a certificate
to overflow an arbitrary number of bytes containing the `.' character
(decimal 46) on the stack. This buffer overflow could result in a crash
(causing a denial of service).

In a TLS client, this can be triggered by connecting to a malicious
server. In a TLS server, this can be triggered if the server requests
client authentication and a malicious client connects.

OpenSSL versions 3.0.0 to 3.0.6 are vulnerable to this issue.

OpenSSL 3.0 users should upgrade to OpenSSL 3.0.7.

OpenSSL 1.1.1 and 1.0.2 are not affected by this issue.

This issue was discovered on 18th October 2022 by Viktor Dukhovni while
researching CVE-2022-3602. The fixes were developed by Dr Paul Dale.

We have no evidence of this issue being exploited as of the time of
release of this advisory (November 1st 2022).

References
==========

URL for this Security Advisory:
https://www.openssl.org/news/secadv/20221101.txt

Note: the online version of the advisory may be updated with additional details
over time.

For details of OpenSSL severity classifications please see:
https://www.openssl.org/policies/secpolicy.html

The vulnerability is a buffer overflow in the X.509 certificate verification, which is the code used to validate TLS certificates. The vulnerability could potentially be exploited to allow remote code execution via a malicious TLS certificate; however, it requires that the malicious TLS certificate be signed by a trusted CA.

Since certificate verification is typically done on the client side, this vulnerability primarily affects clients not servers. There is a case where servers could be exploited via TLS Client Authentication, which may bypass the CA signing requirements as client certs are usually not required to be signed by a trusted CA. Since client authentication is rare ,and most servers do not have it enabled, server exploitation should be low risk.

Attackers could exploit this vulnerability by directing client to a malicious TLS server which uses a specially crafted certificate to trigger the vulnerability.

Affected Systems

Important Note: OpenSSL 3 is not the same as SSLv3. This vulnerability exists only in OpenSSL Version 3 and not SSLv3.

The vulnerability affects only OpenSSL version 3.0.0 to 3.0.6, with the patch being shipped in version 3.0.7. Due to the fact OpenSSL 3.0.0 was released in September 2021, it is far less widespread than previous versions. Given the very recent release date, older appliances with hardcoded OpenSSL version are unlikely to be vulnerable.

NCSC-NL has a helpful list of confirmed affected/unaffected software here: https://github.com/NCSC-NL/OpenSSL-2022/tree/main/software

How To check the version

**OpenSSL library are typically named libcrypto.so or libssl.so on Linux, and libcrypto.dll or libssl.dll on Windows. The filename may sometimes contain the version number at the end, but this is not always the case. The best method is to extract the OpenSSL version number from the file’s content using a combination of strings and RegEx.

Below I’ve attached an example version scanner for Linux and Windows. Please note, these are only example scripts and not designed for production use. Use with care, and note they are not 100% guaranteed to find every OpenSSL library on the server.

openssl version –a

Linux & *Nix Scanner (Bash Script): https://github.com/MalwareTech/SpookySSLTools/blob/main/openssl_scan.sh

Windows scanner (PowerShell): https://github.com/MalwareTech/SpookySSLTools/blob/main/openssl_scan.ps1

Statically Linked Software

Sometimes software is built in such a way that all the libraries (usually DLL or SO) files are simply compiled into the main software executable. This is the worst case and hardest to deal with.

How To Detect
Using something similar method to the above scripts but for executables instead of libraries.

Unix-like:

strings /path/to/executable | grep "^OpenSSL\s*[0-9].[0-9].[0-9]"

Windows: select-string -Path

C:\path\to\executable.exe -Pattern “OpenSSL\s*[0-9].[0-9].[0-9]” -AllMatches | % { $_.Matches } | % { $_.Value }

Credits

Vulnerability Credit: Polar Bear (SandboxEscaper)
https://blog.checkpoint.com/2022/11/01/openssl-vulnerability-cve-2022-3602-remote-code-execution-and-cve-2022-3786-denial-of-service-check-point-research-update/
https://www.malwaretech.com/2022/11/everything-you-need-to-know-about-the-openssl-3-0-7-patch.html