The network administrator at Spears Technology, Inc has configured the default gateway Cisco router's access-list as below: You are hired to conduct security testing on their network. You successfully

Cisco TFTP has no default password because TFTP is an unauthenticated protocol; access to configuration files via TFTP is controlled entirely by router configuration, not built-in credentials.

Because SNMP responses are sent back to the source IP of the request, an attacker sniffing on the local network segment can capture the configuration data the router returns, even though the attacker cannot initiate a direct authenticated connection from their real IP.

GRE encapsulates traffic between two configured tunnel endpoints but does not change the source IP seen by an ACL, so it cannot be used to impersonate a permitted IP range and bypass the access-list.

The router's ACL permits SNMP access only from the 192.168.1.0 range - by crafting an SNMP set request with a spoofed source IP within that permitted range, the ACL check passes and the router processes the request, sending the configuration back toward the spoofed address.