MERLIN LEGEND Communications System Release 6.0
System Programming
555-660-111 Issue 1
February 1998
Customer Support Information
PageA-14Toll Fraud Prevention
A
Security Risks Associated w ith the Automated Attendant Feature of Voice Messaging Systems 1
Two areas of toll fraud risk associated with the Automated Attendant feature of
voice messaging systems are the following:
■Pooled facility (line/trunk) access codes are translated to a menu prompt to
allow Remote Access. If a hacker finds this prompt, the hacker has
immediate access. (In Release 3.1 and later systems, dial access to pools
is initially factory-set to restrict all extensions: to allow pool access, this
restriction must be removed by the system manager.)
■If the Automated Attendant prompts callers to use Remote Call Forwarding
(RCF) to reach an outside telephone number, the system may be
susceptible to toll fraud. An example of this application is a menu or
Submenu that says, “To reach our answering service, select prompt
number 5,” and transfers a caller to an external telephone number.
■Remote Call Forwarding can only be used securely when the central office
provides “reliable disconnect” (sometimes referred to as forward
disconnect or disconnect supervision), which guarantees that the central
office will not return a dial tone after the called party hangs up. In mos t
cases, the central office facility is a loop-start line/trunk which does not
provide reliable disconnect. When loop-start lines/trunks are used, if the
calling party stays on the line, the central office will return a dial tone at the
conclusion of the call, enabling the caller to place another call as if it were
being placed from your company. Ground-start trunks provide reliable
disconnect and should be used whenever possible.
Preventive Measures 1
Take the following preventive measures to limit the risk of unauthorized use of the
Automated Attendant feature by hackers:
■

Do not

use Automated Attendant prompts for Automatic Route Selection
(ARS) Codes or Pooled Facility Codes.
■Assign all unused Automated Attendant Selector Codes to zero, so that
attempts to dial these will be routed to the system attendant.
■If Remote Call Forwarding (RCF) is required, MERLIN LEGEND
Communications System owners should coordinate with their Lucent
Technologies Account Team or authorized dealer to verify the type of
central office facility used for RCF. If it is a ground-start line/trunk, or if it is a
loop-start line/trunk and central office reliable disconnect can be ensured,
then nothing else needs to be done.