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Security Best Practice: MGCP Protocol Enforcement

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Check Point Reference: SBP-2006-16
Date Published:
Severity:
Source: SmartDefense Research Center
Protection Provided by: Security Gateway
  • R70
VPN-1
  • NGX R65
VSX
  • NGX R65
Who is Vulnerable?
MGCP servers
Vulnerability Description
MGCP is an implementation of the Media Gateway Control Protocol architecture[1] for controlling Media Gateways on Internet Protocol (IP) networks and the public switched telephone network (PSTN).
MGCP is a signaling and call control protocol used within Voice over IP (VoIP) systems that typically interoperate with the public switched telephone network (PSTN).
MGCP uses the Session Description Protocol (SDP) for specifying and negotiating the media streams to be transmitted in a call session and the Real-time Transport Protocol (RTP) for framing of the media streams.
Vulnerability Details
If there are illegal characters in an MGCP message header the message may be incorrectly parsed, the parser may crash, the message may be incorrectly handled, and there may be Denial of Service.
 
If an MGCP server is flooded with requests that use commands the server does not support, the server may be overloaded. This could affect customer's service levels.

RFC 3350 section 14 states "RTP may be sent via IP multicast, which provides no direct means for a sender to know all the receivers of the data sent and therefore no measure of privacy. Rightly or not, users may be more sensitive to privacy concerns with audio and video communication than they have been with more traditional forms of network communication".

Protection Overview
This protection detects and blocks MGCP traffic according to the following options:

Blocked/Allowed Commands makes it possible to block commands that the MGCP server does not support or that the administrator does not want the server to handle.

Verify MGCP Header Content validates that the MGCP message header does not contain illegal binary characters; MGCP messages containing illegal characters are blocked.

Drop Multicast RTP Connections blocks multicast RTP packets from crossing the gateway.

To configure the defense, select your product from the list below and follow the related protection steps.

Security Gateway R70

How Can I Protect My Network?
1. In the IPS tab, click Protections > By Protocol > Application Intelligence > VoIP.
2. In the right pane, double-click the following protections:

MGCP

3. In the Protection Details window, click on Edit. Choose the protection's Action (Override IPS Policy with: Prevent/Detect), and apply Additional Settings.
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: MGCP content security violation
Attack Information:
broadcast/multicast addresses are not accepted (client)
broadcast/multicast addresses are not accepted (server)

VPN-1 NGX R65 & VPN-1 VSX NGX R65

How Can I Protect My Network?
1. In the SmartDefense tab, click Application IntelligenceVoIP > MGCP.
2. In the configuration pane, under Settings > Mode, check Active.
3. The protection can be applied either to all HTTP traffic or to selected web servers.
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: MGCP content security violation
Attack Information:
broadcast/multicast addresses are not accepted (client)
broadcast/multicast addresses are not accepted (server)