Pass the Huawei HCIA-Security H12-711_V4.0 Questions and answers with CertsForce

Intrusion Prevention (IPS) detects and blocks attacks primarily by analyzing traffic patterns and payload characteristics against known signatures, protocol anomalies, and behavioral rules. Many common application-layer exploits have recognizable request structures that IPS engines can match.

An injection attack (such as SQL injection or command injection) typically contains suspicious characters, keywords, and abnormal parameter patterns within application requests. IPS signatures can detect these malicious payload characteristics and either block the session or generate alarms. Directory traversal attacks also have distinct patterns, such as attempts to access unauthorized paths using sequences like ../ (or encoded variants). These are classic web-attack signatures commonly covered by IPS rule sets. Buffer overflow attacks often exploit protocol or application parsing weaknesses by sending overly long fields, malformed headers, or abnormal protocol sequences; IPS can detect these through signature matching and protocol anomaly detection.

A Trojan horse , however, is malware residing on an endpoint (often delivered via files, email attachments, downloads, or user execution). While some network security features (like antivirus/URL filtering/sandboxing) may detect Trojan delivery or command-and-control traffic, “Trojan horse” itself is not typically classified as an IPS-detected attack type in this context. Therefore, A, B, and D are correct.

A Denial of Service attack is intended to make a host, server, or network service unavailable to legitimate users. It usually works by exhausting system resources such as bandwidth, CPU, memory, connection tables, or buffers, so valid users cannot access the service normally. Therefore, statement B is correct because the essential purpose of a DoS attack is to interrupt services or block resource access on the target.

Statement C is also correct. Many DoS attacks attempt to consume queue space, session resources, or buffers on the target so that new connection requests cannot be processed. This is a common way of making a service unavailable. Statement A can also be correct in the context of some DoS methods, because attackers may use IP spoofing to hide their identity, bypass simple filtering, or increase the difficulty of tracing the attack source.

Statement D is incorrect because DoS attacks are designed to affect availability , not to create unrecoverable physical damage to hardware. They may crash systems, overload services, or interrupt access, but they do not normally destroy the target device physically.

Explanation From HCIA-Security documents:

In a PKI, certificate revocation is mainly about requester authentication and approval, not about using one mandatory communication method. The RA is responsible for verifying the applicant’s identity and the legitimacy of the revocation request, then submitting the validated request to the CA. After approval, the CA updates the certificate status, typically by publishing an updated CRL or providing status through OCSP, so relying parties can detect that the certificate is no longer trustworthy.

A “signed and encrypted email” is only one possible way to send a revocation request, but it is not required. In practice, organizations may accept revocation requests through a portal, ticketing system, dedicated PKI management interface, phone with pre-agreed authentication, or other controlled channels. If email is used, digital signature can help prove the requester’s identity and protect integrity, while encryption is optional and depends on policy because the key need is authorization, not confidentiality.

Explanation From HCIA-Security documents:

In ESP transport mode, the authentication function provides data integrity and origin authentication for specific parts of the IP packet. The authentication calculation covers the ESP header, TCP/UDP header, user data, and ESP tail (including padding, Pad Length, and Next Header fields) . However, it does not include the outer IP header, because some IP header fields (such as TTL) may change during packet forwarding. It also does not include the ESP Authentication Data field itself, since that field stores the integrity check value result of the calculation.

In the diagram, range 3 correctly represents the portion starting from the ESP header up to the ESP tail, excluding the IP header and excluding the ESP Authentication Data field.

Range 1 only covers part of the payload, range 2 does not include the ESP header, and range 4 incorrectly includes the IP header. Therefore, option 3 accurately describes the authentication scope of ESP in transport mode.

In IPsec ESP transport mode , the authentication process protects most of the ESP packet except the outer IP header and the authentication data field itself. Specifically, the authentication calculation covers the ESP header, the encrypted payload (such as the TCP header and application data), and the ESP trailer . The IP header is not included , because it may change during packet transmission, and the ESP authentication data field is also excluded because it stores the result of the authentication calculation.

Looking at the packet structure in the figure, the order is: IP Header → ESP Header → TCP Header → Data → ESP Tail → ESP Auth Data . The correct authentication range therefore begins at the ESP header and ends at the ESP tail , but it does not include the IP header or the ESP authentication data.

In the diagram, option 3 represents the range starting from the ESP header and ending at the ESP tail , which matches the actual authentication coverage of ESP in transport mode. Therefore, the correct answer is 3 .