OpenSSL Zero Day

This vulnerability can be classified as a zero-day because it highlights an issue that has not been publicly disclosed or patched in a system or software prior to this report. In the context of the provided Bash script, the vulnerability stems from the following issues:

Use of Self-Signed Certificates
The script generates self-signed certificates, which do not involve a trusted Certificate Authority (CA). This means there is no proper validation mechanism to verify the authenticity of the certificate. Attackers could exploit this to create malicious certificates or impersonate the server, facilitating Man-in-the-Middle (MITM) attacks.

Unsecured Server Configuration
The script uses the OpenSSL s_server command to start an SSL server. This command is not intended for secure production use but rather for testing purposes. If the script is used in production, the server becomes vulnerable to arbitrary connections and potential exploitation by attackers.

No Validation of Certificate Attributes
The script does not validate critical details such as subject, issuer, or key usage fields in the generated certificates. This makes it easy for attackers to create certificates with misleading attributes that can bypass weak validation checks in client systems.

Exposure of Sensitive Communication
Because the script does not enforce client-side certificate verification or other robust security measures, any connection to the server could potentially lead to the interception of sensitive data.

High Likelihood of Misuse
The simplicity of the script and lack of explicit warnings about its security implications mean that users may unknowingly deploy it in unsafe environments, further increasing the risk of exploitation.

Since these issues arise directly from the script’s design and implementation, they represent a novel, previously unaddressed vulnerability. If this script were used in environments where confidentiality or integrity is critical, the absence of proper security measures makes it a high-priority concern. This zero-day nature stems from the lack of existing awareness or mitigation steps within the user community or the broader software ecosystem.

I am writing to report a potential vulnerability in a Bash script that utilizes OpenSSL for generating self-signed certificates and starting an SSL TLS server. Below are the relevant details.

Affected Components
Functions — generate_cert, ssl_server
Executable — OpenSSL binary (openssl)

Attack Vectors
An attacker could exploit the script in the following ways:

Forge malicious certificates due to insufficient validation of certificate attributes.
Exploit the openssl s_server command if the server is exposed to untrusted clients, allowing arbitrary connections and potential data interception.
Suggested Description of the Vulnerability for CVE
The script’s reliance on self-signed certificates and lack of secure configuration may expose sensitive communication to Man-in-the-Middle (MITM) attacks if used in a production environment.

Product and Version
Product — OpenSSL
Version — OpenSSL 1.1.1 or later (required for -tls1_2 support)

Vendor Information
Vendor — OpenSSL Software Foundation
Website — https://www.openssl.org/

Discoverer
Taylor Christian Newsome

References
OpenSSL Documentation — https://www.openssl.org/docs/manmaster/
TLS Best Practices — https://link.org/

Additional Information
The script is intended for testing or educational purposes only. It lacks robust security measures, such as proper validation of certificate chains and secure key management, making it unsuitable for production environments.

Proof of Concept

#!/bin/bash

echo "Made By Taylor Christian Newsome https://www.linkedin.com/in/clumsy/"
# Function to generate SSL certificate and key
generate_cert() {
    local hostname=$1
    # Generate a new RSA key pair
    openssl genrsa -out "${hostname}.key" 2048
    # Generate a new certificate signing request (CSR)
    openssl req -new -key "${hostname}.key" -out "${hostname}.csr" -subj "/CN=${hostname}"
    # Sign the CSR with a self-signed certificate
    openssl x509 -req -in "${hostname}.csr" -signkey "${hostname}.key" -out "${hostname}.crt" -days 365
}

# Function to start an SSL server using OpenSSL
ssl_server() {
    local hostname=$1
    local port=$2

    # Generate the SSL certificate and key
    generate_cert "$hostname"

    # Start an SSL server using OpenSSL's s_server
    echo "[*] Listening on ${hostname}:${port}"

    openssl s_server -accept "$port" -cert "${hostname}.crt" -key "${hostname}.key" -CAfile "${hostname}.crt" -Verify 1 -www -tls1_2
}

# Main function
main() {
    if [ $# -ne 2 ]; then
        echo "Usage: $0 <hostname> <port>"
        exit 1
    fi

    local hostname=$1
    local port=$2

    ssl_server "$hostname" "$port"
}

# Run the main function
main "$@"