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MERLIN LEGEND Communications System Release 6.1
Network Reference
555-661-150
Issue 1
August 1998
Customer Support Information
Page A-14Toll Fraud Prevention
A
■ All voice messaging system users must use secure passwords known only
to the user.
Security Risks Associated with 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
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 be used securely only when the central office
provides “reliable disconnect” (sometimes referred to as forward
disconnect or disconnect supervision), which guarantees that the central
office does not return a dial tone after the called party hangs up. In most
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 does 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 ARS Codes or Pooled Facility
Codes.
■ Assign all unused Automated Attendant Selector Codes to zero, so that
attempts to dial these are routed to the system attendant.
■ If Remote Call Forwarding 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.