ISC2 Exam ISSMP Topic 4 Question 57 Discussion

Port signatures watch for connection attempts to well-known, frequently attacked ports. These type of signatures are used in Network-based ID systems, which involve looking at the packets on the network as they pass by some sensor. The packets are identified to be of interest if they match a signature.

Answer option D is incorrect. String signatures look for a text string that indicates a possible attack.

Answer option C is incorrect. Header signatures watch for dangerous or illogical combinations in packet headers.

Answer option B is incorrect. Digital signature is an authentication tool that is used to ensure the integrity and non-repudiation of a presentation. It is used to authenticate the presentation by using a cryptographic mechanism. The document for a digital signature can be a presentation, a message, or an email.