
Oracle SBC Security Guide
Basic DDoS configuration settings are outlined in the other appendices. However, for the best DDoS
protection, the configuration should be customized based on the customer environment and the traffic
levels they actually receive.
DoS settings that help mitigate SIP scanning risks are also depicted below.
Header Manipulation Rules for Scanner Mitigation
SIP Header Manipulation Rule Logic
One way to drop all packets sent from an endpoint running an SIP scanner is to use a combination of SIP
Manipulation Rules in conjunction with a dummy Session Agent. In this case, a dummy session agent is
defined that is not an externally routable target.
As a message enters the SBC it is passed by the SIP interface to the incoming HMR. The HMR applies a
regular expression against the message to determine if it is a scanning tool. If there is a match, the HMR
can take action to mark it as invalid by inserting an additional route header and forwarding it to a
“dummy” session agent. Provisioning the dummy session agent with the state disabled will cause the call
to be refused. Custom mapping this to a unique error response can in turn be used in conjunction with a
sip-interface option configurable to drop specific error responses.
Below is a flow diagram of how a SIP REGISTER message with a User-Agent header of “friendly-
scanner” will be dropped.
REGISTER Message
User-Agent: friendly-scanner
SIP Interface – drop response
Access Realm
Core Realm
hostname 10.12.13.14
State disabled
local-response-map 503Rogue
Inbound Realm
SIP Manipulation Rule
if “User-Agent: friendly-scanner”
Add a new Route header
"< sip:10.12.13.14;lr >"
Session Agent
Create to dummy
address specified in
the HMR added
Route header.
Disable to create
“503” response
SIP Response Map
503Rogue
503 -> 677 (Rogue)
Drop
Options
dropResponse=677
SIP Interface
Map the “503”
response to a new
response code
“677”, that can be
dropped at the
access SIP
Interface
Configure options to
drop all “677”
responses
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