CAS-005 Exam Dumps - CompTIA SecurityX Certification Exam

Analysis and Remediation Options for Each IoC:

IoC 1:

Evidence:

Source: Apache_httpd

Type: DNSQ

Dest: @10.1.1.1:53,@10.1.2.5

Data: update.s.domain, CNAME 3a129sk219r9slmfkzzz000.s.domain, 108.158.253.253

Analysis:

Analysis: The service is attempting to resolve a malicious domain.

Reason: The DNS queries and the nature of the CNAME resolution indicate that the service is trying to resolve potentially harmful domains, which is a common tactic used by malware to connect to command-and-control servers.

Remediation:

Remediation: Implement a blocklist for known malicious ports.

Reason: Blocking known malicious domains at the DNS level prevents the resolution of harmful domains, thereby protecting the network from potential connections to malicious servers.

IoC 2:

Evidence:

Src: 10.0.5.5

Dst: 10.1.2.1, 10.1.2.2, 10.1.2.3, 10.1.2.4, 10.1.2.5

Proto: IP_ICMP

Data: ECHO

Action: Drop

Analysis:

Analysis: Someone is footprinting a network subnet.

Reason: The repeated ICMP ECHO requests to different addresses within a subnet indicate that someone is scanning the network to discover active hosts, a common reconnaissance technique used by attackers.

Remediation:

Remediation: Block ping requests across the WAN interface.

Reason: Blocking ICMP ECHO requests on the WAN interface can prevent attackers from using ping sweeps to gather information about the network topology and active devices.

IoC 3:

Evidence:

Proxylog:

GET /announce?info_hash=%01dff%27f%21%10%c5%wp%4e%1d%6f%63%3c%49%6d&peer_id%3dxJFS

Uploaded=0&downloaded=0&left=3767869&compact=1&ip=10.5.1.26&event=started

User-Agent: RAZA 2.1.0.0

Host: localhost

Connection: Keep-Alive

HTTP200 OK

Analysis:

Analysis: An employee is using P2P services to download files.

Reason: The HTTP GET request with parameters related to a BitTorrent client indicates that the employee is using peer-to-peer (P2P) services, which can lead to unauthorized data transfer and potential security risks.

Remediation:

Remediation: Enforce endpoint controls on third-party software installations.

Reason: By enforcing strict endpoint controls, you can prevent the installation and use of unauthorized software, such as P2P clients, thereby mitigating the risk of data leaks and other security threats associated with such applications.

The logs show the device checking in from two distant locations (USA and Qatar) at nearly the same time, which indicatesimpossible travel— a strong indicator that either the device has been cloned, compromised, or credentials stolen. The best immediate action is todisable the device's account and accessto prevent potential misuse while an investigation is conducted. Malicious application installation or resource issues are possible but secondary concerns here compared to account compromise.

Enriching data to compare domains requires actionable visibility. Let’s analyze:

A. Cron job:Automates updates but doesn’t analyze in the SIEM.

B. Parser:Processes logs but doesn’t provide comparison insights.

C. Filter query:Excludes matches, opposite of enrichment.

Step-by-Step Explanation:

Sigma (A) is a rule-based detection language that is vendor-agnostic, meaning it can be used across different SIEM (Security Information and Event Management) tools. Unlike YARA (B), which focuses on file-based detection, Sigma provides a standardized way to create rules that work across various security platforms.

The logs show that the user connected fromToronto (104.18.16.29)andLos Angeles (95.67.137.12)within minutes. The sudden location change is a typical trigger forgeoblocking in a Next-Generation Firewall (NGFW), leading to theHR System being denied.

A compromised account (B)would show failed login attempts or unusual activities, but all other access attempts were allowed.

Business hours restriction (C)is unlikely since the user was granted access earlier.

Approved subnet issues (D)would affect all applications, not just HR System access.

Implementing digital signatures ensures the integrity and authenticity of software binaries. When a binary is digitally signed, any tampering with the file (e.g., replacing it with amalicious version) would invalidate the signature. This allows systems to verify the origin and integrity of binaries before execution, preventing the execution of unauthorized or compromised binaries.

A. Improving patching processes: While important, this does not directly address the issue of verifying the integrity of binaries.

B. Implementing digital signatures: This ensures that only valid, untampered binaries are executed, preventing attackers from substituting legitimate binaries with malicious ones.

C. Performing manual updates via USB ports: This is not practical and does not scale well, especially in large environments.

D. Allowing only files from internal sources: This reduces the risk but does not provide a mechanism to verify the integrity of binaries.