Conducting Forensic Analysis and Incident Response Using Cisco Technologies for CyberOps (CBRFIR)

When suspicious activity is detected on a workstation, immediate steps need to be taken to preserve evidence and prevent further compromise:

Disconnecting the system from the network (C)is crucial to stop potential exfiltration of data or ongoing communications with a command-and-control server. This isolation prevents further spread or damage while preserving the state of the compromised system for further investigation.

Taking an image of the workstation (E)is part of the forensics acquisition process. It involves creating a bit-by-bit copy of the system's disk, which preserves all evidence in its current state. This allows for thorough forensic analysis without affecting the original evidence.

These steps align with the best practices outlined in the incident response and forensics processes (as described in theCyberOps Technologies (CBRFIR) 300-215 study guide). Specifically, in theIdentification and Containment phases of the incident response cycle, it's emphasized that isolating the system and preserving evidence through imaging are critical to ensuring both containment of the threat and successful forensic investigation.
References:
CyberOps Technologies (CBRFIR) 300-215 study guide, Chapter:
Understanding the Security Incident Response Process, Identification and Containment Phases, page 102-
104 .

The log entry shows a failed SSH login attempt for an invalid user "admin" from IP192.168.1.100. As the system has just gone live and no legitimate use is expected, this could be an early reconnaissance or brute-force attempt. However, blocking IPs or resetting passwords without fully understanding the context could lead to incomplete remediation or false positives.

According to Cisco CyberOps best practices, the first step is to thoroughly investigate the alert by correlating it with other logs (e.g., authentication logs, IDS/IPS logs) to determine the intent and scope of activity.

The Cisco study material recommends integrating automation for log/event collection and contextual analysis to reduce detection delays and ensure rapid identification of anomalies. It also emphasizes the need for pre-defined roles and documented steps in an Incident Handling Playbook , following NIST SP 800-61 Rev.2 standards, to improve consistency and readiness during incidents.

The alert shown is based on a Snort rule for a Unicode directory traversal attack against IIS web servers (Microsoft platform). The key detail here is the payload content"../..%c0%af../"which is a classic IIS-specific exploit related to CVE-2000- 0884 .

Since the company only uses Unix systems , they are not vulnerable to this IIS-specific attack. Therefore, these alerts are triggered by irrelevant traffic or misapplied signatures, resulting in False Positives .

In the recovery phase , the goal is to restore affected systems to normal operations and ensure the threat has been completely eradicated. According to the CyberOps Associate guide:

"This phase may include restoring data from clean backups, replacing compromised systems, and the re-installation of the Operating System (OS) and applications".

According to the MITRE ATT&CK matrix, when encrypted traffic is tunneled through a legitimate protocol such as HTTP (port 80) to a non-malicious domain, this aligns with the tactic "Exfiltration Over Asymmetric Encrypted Non-C2 Protocol" (T1048.002). The attacker is trying to hide exfiltration in otherwise benign traffic.

The-hoption in theobjdumpcommand displays section headers of an object file. According to general usage and command-line documentation, and also explained in digital forensics tools discussions in the CyberOps course, the header information includes details about the name, size, VMA, LMA, file offset, and alignment of each section in the object file. This helps analysts understand how data is stored and organized within compiled files during forensic examinations.

If IPS and SIEM logs do not give enough insight into a file's behavior, the next logical step is to review the Antivirus solution logs. These logs often provide detailed behavior analytics such as:

File actions and access patterns

Registry modifications

File execution history

The Cisco CyberOps guide emphasizes AV logs as critical forensic artifacts for understanding endpoint-based infections, especially when beaconing or suspicious activity is suspected.

The PowerShell cmdlet Get-Content reads content line-by-line from a file and is commonly used for processing logs or large text files. When combined with Select-String, it can search for specific patterns (such as "ERROR" or "SUCCESS") within those lines and return a collection of matching objects, including metadata like line number and line content.

Cisco Firepower Management Center (FMC), when configured with Snort rules, classifies attacks with signature categories such as FILE-OFFICE for Microsoft Office-based exploits. One of the critical threats involving Microsoft Office is a known vector involving Microsoft Graphics, which attackers exploit for remote code execution (RCE) . RCE vulnerabilities enable attackers to execute arbitrary commands or code on the target machine--making this classification high-severity.

The alert "FILE-OFFICE Microsoft Graphics remote code execution attempt" is consistent with what Cisco and Snort define for such threats and appears in rulesets addressing vulnerabilities like CVE-2017-0001.

References:
Cisco Secure Firewall Threat Defense and Snort rule categories in the Cisco CyberOps v1.2
Guide.