Configuring Sip Message Policy Rules - AudioCodes Mediant 500 E-SBC User Manual

Parameter
18.5

Configuring SIP Message Policy Rules

The Message Policy table lets you configure up to 20 SIP Message Policy rules. SIP
Message Policy rules are used to block (blacklist) unwanted incoming SIP messages or
permit (whitelist) receipt of desired SIP messages. You can configure legal and illegal
characteristics of a SIP message. This feature is helpful against VoIP fuzzing (also known
as robustness testing), which sends different types of packets to its "victims" for finding
bugs and vulnerabilities. For example, the attacker might try sending a SIP message
containing either an oversized parameter or too many occurrences of a parameter.
To apply SIP Message Policy rules, you need to assign them to SIP Interfaces associated
with the relevant IP Groups (see ''Configuring SIP Interfaces'' on page 258).
Each Message Policy rule can be configured with the following:

Maximum message length

Maximum header length

Maximum message body length

Maximum number of headers

Maximum number of bodies

Option to send 400 "Bad Request" response if message request is rejected

Blacklist and whitelist for defined methods (e.g., INVITE)

Blacklist and whitelist for defined bodies
The following procedure describes how to configure Message Policy rules in the Web
interface. You can also configure Message Policy rules using the table ini file parameter,
MessagePolicy or the CLI command, configure voip > sbc message-policy.

To configure SIP Message Policy rules:
1. Open the Message Policy Table page (Configuration tab > VoIP menu > SIP
Definitions > Msg Policy & Manipulation > Message Policy Table).
User's Manual
Notes:

When configured to Use Previous Condition, the 'Message
Type' and 'Condition' parameters are not applicable and if
configured are ignored.

When multiple manipulation rules apply to the same header, the
next rule applies to the resultant string of the previous rule.
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Mediant 500 E-SBC
Description
Document #: LTRT-10437