300-740 Questions and Answers

According to the SCAZT documentation, web application firewalls (WAFs) designed to protect against zero-day Distributed Denial of Service (DDoS) attacks leverage adaptive and behavioral-based algorithms. These algorithms dynamically analyze traffic patterns, baseline normal behavior, and detect anomalies that could indicate novel or zero-day attacks. Unlike signature-based detection, adaptive and behavioral methods adjust in real-time to emerging threats, learning from ongoing traffic without relying on pre-defined rules. This proactive approach enables rapid detection and mitigation of unknown DDoS vectors, critical for cloud and network security where threats evolve constantly.

Rule 3 denies all DNS traffic from the subnet 10.1.0.0/30, which includes the client at 10.1.0.6. Since DNS resolution is required to resolve www.salesforce.com, this DNS deny rule is preventing the client from obtaining the IP address needed for HTTPS connection. Removing Rule 3 allows DNS traffic from the client, while Rule 4 permits it specifically for the 4.4.4.4 DNS server.

As per SCAZT Section 3: Network and Cloud Security (Pages 70–73), DNS resolution must be allowed before HTTPS connectivity is attempted. Rule priority and traffic dependency should always be considered in firewall design.

Rule 1 is a “deny all” rule placed at the top of the access control policy. Because Cisco firewalls process rules sequentially from top to bottom, Rule 1 is blocking all traffic—including RDP (Rule 2) and HTTPS (Rule 3). To allow specific traffic, the “deny all” catch-all rule should be placed last so that the specific allow rules are evaluated first.

SCAZT Section 3 (Network and Cloud Security, Pages 69–74) discusses rule hierarchy and clearly states that allow rules must precede any general deny policies to ensure intended traffic is matched correctly. This best practice is essential when dealing with multi-cloud access control.

When configuring Cisco Umbrella to block all traffic except to domains explicitly allowed (e.g., cisco.com), the “Allow-Only Mode” must be enabled. This setting overrides default behavior and ensures that only entries listed in the allow list are accessible—everything else is automatically blocked. According to SCAZT Section 1 (Cloud Security Architecture, Pages 16–19), enabling Allow-Only Mode is crucial for strict outbound DNS filtering.

Without this setting, the system allows access to all domains not explicitly blocked, which is why the engineer was able to access non-cisco.com domains despite defining an allow list.

To enforce both user-based and device-based authentication on Cisco ASA, the tunnel group must include the command: authentication aaa certificate. This configuration requires that both a valid username/password (authenticated via AAA, such as Active Directory) and a trusted certificate (device identity) are present before allowing VPN access. Without this directive, only username/password credentials are validated, which leads to the scenario described in the question.

The SCAZT documentation emphasizes that when Cisco Secure XDR identifies a high-risk threat (e.g., risk score 8 out of 10 for malware distribution, as shown in the exhibit), the first priority is to prevent lateral movement and data exfiltration. The recommended first response action is to isolate the affected endpoint from the network.

Cisco Secure Endpoint and XDR allow you to trigger an "isolate" response directly from the dashboard, cutting off all non-management communication from the compromised device. This preserves the environment and enables forensic analysis before removing malware or taking destructive actions like rebuilding the system.

From the firewall access rules provided, Rule 1 allows traffic from 20.1.1.10 (GCP VM) to 20.1.1.1 using HTTPS. However, this destination is not the actual mail server—the mail server resides at 192.168.200.10 (inside network). Therefore:

A: Rule 1 must be updated to reflect the correct destination: 192.168.200.10. Without this change, traffic is not permitted to the mail server.

D: NAT (Network Address Translation) is needed to translate the external address (e.g., 20.1.1.10) to access internal addresses (like 192.168.200.10). As per SCAZT and Cisco firewall policies, NAT enables proper packet delivery from public to private zones.

Rule 2, which denies all other traffic, is correctly placed after the specific allow rule. Therefore, moving it (Option B) would not help, and Options C and E are unrelated to resolving the immediate firewall access and routing issue.

The error %OPENDNS-3-DNS_RES_FAILURE indicates a failure to resolve DNS queries via Cisco Umbrella. The most common cause of this error is the router lacking DNS resolution capability. To resolve this, the router must be explicitly configured to use Cisco Umbrella’s OpenDNS servers by adding the following to global configuration:

According to the SCAZT guide (Section 1: Cloud Security Architecture, Pages 17–19), Umbrella enforces cloud-based DNS-layer protection, and upstream devices must be properly configured with working DNS name servers to perform redirection and inspection.

In the provided screenshot of Cisco Secure Firewall Management Center (FMC), the rule labeled "Block Facebook" is intended to block access to Facebook and Facebook Apps. However, the rule lacks correct zone configurations, which is why the block is ineffective.

Per Cisco's best practices outlined in the Designing and Implementing Secure Cloud Access for Users and Endpoints (SCAZT) documentation and Cisco Secure Firewall documentation:

The source zone should reflect where the traffic is originating from—in this case, from internal users. Therefore, Source Zone must be set to inside (Answer: E).

The destination zone should reflect where the traffic is headed—in this case, towards the internet. So, Destination Zone must be set to outside (Answer: D).

Without properly defining source and destination zones, FMC rules may not match the traffic correctly, resulting in traffic being incorrectly allowed.

To enable VPN load balancing with secure encryption between Cisco ASA firewalls, two additional commands are required:

encryption aes 256: Defines the encryption scheme used in the load balancing cluster. Without specifying encryption, secure key exchanges between devices will not occur properly.

cluster encryption: Enables encrypted communication between the clustered ASA devices. Without this command, cluster member synchronization is not securely established.

The commands shown in the exhibit correctly configure the cluster key and virtual IP but lack the necessary encryption parameters. According to Cisco’s VPN load balancing implementation guides and reinforced in the SCAZT documentation, these two settings are required to secure the VPN session load distribution.

A drive-by compromise occurs when malicious code is automatically downloaded and executed simply by visiting a compromised website—often through malicious advertising scripts (malvertising). According to SCAZT Section 4: Application and Data Security (Pages 85–87), ad blockers help prevent drive-by downloads by blocking these third-party ad scripts and redirections, which are commonly used in such attacks.

VPNs and private browsing modes (e.g., Incognito) do not provide protection against malicious content hosted on web pages.

The flow data in the exhibit shows multiple short-duration, high-volume HTTPS connections (443/TCP) from IP 10.10.10.10 to multiple destination IPs in the 50.10.10.0/24 network. All flows are 22 seconds long and transfer exactly 1.77M of data. This uniform behavior to a large set of IP addresses strongly indicates a Denial of Service (DoS) pattern, where an internal host (10.10.10.10) is overwhelming external systems in the 50.10.10.0/24 range.

The SCAZT guide (Section 6: Threat Response, Pages 114–117) explains how Secure Cloud Analytics uses NetFlow and behavioral modeling to identify such volumetric threats. Key identifiers include:

Same connection size (1.77M)

Multiple unique peer IPs in a single external subnet

Same destination port and protocol (HTTPS)

Zero TCP connections completed, indicating unacknowledged connections

This matches the behavioral pattern of a DoS originating from an internal host.

According to the MITRE ATT&CK framework and the SCAZT documentation, one of the most effective mitigation techniques against exploitation is to keep systems updated with the latest patches. Exploitation typically targets known vulnerabilities in operating systems and applications. Timely patching significantly reduces the risk of successful exploitation, especially zero-day vulnerabilities once disclosed.