Preventing security threats in a computer network

1. A method for preventing communication through covert channels in a Local Area Network (LAN), the method comprising:

A) suspending an inbound or an outbound network connection related to a network element for a predetermined period of time;

B) determining if any respective outbound or inbound network connection related to the same or any other network element ceases to transmit for the duration of the time period predetermined in step A);

C) if an outbound or inbound network connection is detected to cease transmission in step B), concluding that the inbound or outbound network connection suspended in step A) and the respective outbound or inbound network connections are connected;

D) detecting whether connected network connections use different transmission protocols; and

E) if the connected network connections are detected to use different transmission protocols, determining that the connected network connections are related to a malicious covert channel and taking action to prevent the malicious covert channel from working.

2. The method according to claim 1 , wherein steps A) to D) are repeated one or more times before the step E) determination is processed.

3. The method according to claim 1 , wherein if the connected network connections are not detected to use different transmission protocols, the method comprises judging the connected network connections as allowed.

4. The method according to claim 1 , wherein taking action to prevent the malicious covert channel from working comprises any of: denying a connection corresponding to said network connections generating an alert including information regarding said connected network connections related to a malicious covert channel.

5. An apparatus, comprising

a memory configured to store computer program code, and

a processor configured to read and execute computer program code stored in the memory,

wherein the processor is configured to cause the apparatus to perform:

A) suspending an inbound or an outbound network connection related to a network element for a predetermined period of time;

B) determining if any respective outbound or inbound network connection related to the same or any other network element ceases to transmit for the duration of the time period predetermined in step A);

C) if an outbound or inbound network connection is detected to cease transmission in step B), concluding that the inbound or outbound network connection suspended in step A) and the respective outbound or inbound network connections are connected;

D) detecting whether connected network connections use different transmission protocols; and

E) if the connected network connections are detected to use different transmission protocols, determining that the connected network connections are related to a malicious covert channel and taking action to prevent the malicious covert channel from working.

6. The apparatus according to claim 5 , wherein said processor is configured to cause the apparatus to perform:

repeating steps A) to D) one or more times before the step E) determination is processed.

7. The apparatus according to claim 5 , wherein if the connected network connections are not detected to use different transmission protocols, the processor is configured to cause the apparatus to judge the connected network connections as allowed.

8. The apparatus according to claim 5 , wherein taking action to prevent the malicious covert channel from working comprises any of: denying a connection corresponding to said network connection, generating an alert including information regarding said connected network connections related to a malicious covert channel.

9. A non-transitory computer storage medium having stored thereon a computer program code for implementing preventing communication through covert channels in a Local Area Network (LAN), comprising:

A) suspending an inbound or an outbound network connection related to a network element for a predetermined period of time;

B) determining if any respective outbound or inbound network connection related to the same or any other network element ceases to transmit for the duration of the time period predetermined in step A);

C) if an outbound or inbound network connection is detected to cease transmission in step B), concluding that the inbound or outbound network connection suspended in step A) and the respective outbound or inbound network connections are connected;

D) detecting whether connected network connections use different transmission protocols; and

E) if the connected network connections are detected to use different transmission protocols, determining that the connected network connections are related to a malicious covert channel and taking action to prevent the malicious covert channel from working.

10. The non-transitory computer storage medium storing the computer program code according to claim 9 , wherein steps A) to D) are repeated one or more times before the step E) determination is processed.

11. The non-transitory computer storage medium storing the computer program code according to claim 9 , wherein if the connected network connections are not detected to use different transmission protocols, and comprising judging the connected network connections as allowed.

12. The non-transitory computer storage medium storing the computer program code according to claim 9 , wherein taking action to prevent the malicious covert channel from working comprises any of: denying a connection corresponding to said network connection, generating an alert including information regarding said connected network connections related to a malicious covert channel.