See the solution in Explanation.
Explanation:
To determine thedate the webshell was accessedfrom theinvestigation22.pcapfile, follow these detailed steps:
Step 1: Access the PCAP File
* Log into the Analyst Desktop.
* Navigate to theInvestigationsfolder on the desktop.
* Locate the file:
investigation22.pcap
Step 2: Open the PCAP File in Wireshark
* LaunchWireshark.
* Open the PCAP file:
mathematica
File > Open > Desktop > Investigations > investigation22.pcap
* ClickOpento load the file.
Step 3: Filter for Webshell Traffic
* Since webshells typically useHTTP/Sto communicate, apply a filter:
http.request or http.response
* Alternatively, if you know the IP of the compromised host (e.g.,10.10.44.200), use:
nginx
http and ip.addr == 10.10.44.200
* PressEnterto apply the filter.
Step 4: Identify Webshell Activity
* Look for HTTP requests that include:
* Common Webshell Filenames:shell.jsp, cmd.php, backdoor.aspx, etc.
* Suspicious HTTP Methods:MainlyPOSTorGET.
* Right-click a suspicious packet and choose:
arduino
Follow > HTTP Stream
* Inspect the HTTP headers and content to confirm the presence of a webshell.
Step 5: Extract the Access Date
* Look at theHTTP request/response header.
* Find theDatefield orTimestampof the packet:
* Wireshark displays timestamps on the left by default.
* Confirm theHTTP streamincludes commands or uploads to the webshell.
Example HTTP Stream:
POST /uploads/shell.jsp HTTP/1.1
Host: 10.10.44.200
User-Agent: Mozilla/5.0
Date: Mon, 2024-03-18 14:35:22 GMT
Step 6: Verify the Correct Date
* Double-check other HTTP requests or responses related to the webshell.
* Make sure thedate fieldis consistent across multiple requests to the same file.
2024-03-18
Step 7: Document the Finding
* Date of Access:2024-03-18
* Filename:shell.jsp (as identified earlier)
* Compromised Host:10.10.44.200
* Method of Access:HTTP POST
Step 8: Next Steps
* Isolate the Affected Host:
* Remove the compromised server from the network.
* Remove the Webshell:
rm /path/to/webshell/shell.jsp
* Analyze Web Server Logs:
* Correlate timestamps with access logs to identify the initial compromise.
* Implement WAF Rules:
* Block suspicious patterns related to file uploads and webshell execution.