Difference between revisions of "Hidden channels"
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'''Hidden channels''' (covert channels) are communication channels that transmit information without the authorization or knowledge of the channel's designer, owner, or operator. | '''Hidden channels''' (covert channels) are communication channels that transmit information without the authorization or knowledge of the channel's designer, owner, or operator. | ||
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* TCP options; | * TCP options; | ||
* etc. | * etc. | ||
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| + | == Detection of hidden channels == | ||
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| + | Generally, it is impossible to detect well-designed hidden channels by means of traffic analysis. For example, information hidden within TLS ''Client/Server Hello'' random bytes in encrypted form cannot be distinguished from bytes produced by secure random number generator. | ||
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| + | However, it is possible to detect hidden channels by detecting attendant events, such as successful intrusion attempts. | ||
== External Links == | == External Links == | ||
Revision as of 14:15, 10 October 2008
Hidden channels (covert channels) are communication channels that transmit information without the authorization or knowledge of the channel's designer, owner, or operator.
Contents |
Common Uses
- Bypassing network filters;
- Bypassing network sniffers.
Techniques
Information can be hidden within:
- IP ID;
- TCP SEQ/ACK numbers;
- TCP options;
- etc.
Generally, it is impossible to detect well-designed hidden channels by means of traffic analysis. For example, information hidden within TLS Client/Server Hello random bytes in encrypted form cannot be distinguished from bytes produced by secure random number generator.
However, it is possible to detect hidden channels by detecting attendant events, such as successful intrusion attempts.
