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LetsDefend - MSHTML#
Created: 15/01/2024 12:02 Last Updated: 19/01/2024 15:14
MSHTML

2021’s 0-Day MSHTML
Challenge Files (pass: infected): Download
This challenge prepared by @Bohan Zhang Malware samples: MalwareBazaar
Start Investigation#
Upon extracting the file, we received two folders: one containing challenge files and another containing tools that can be utilized for their analysis.

I began by using oleid.py from the Oletools suite. Now that we’ve confirmed there’s no VBA script embedded
we can move forward and use oleobj for the remaining tasks.
After run oleobj with Employees_Contact_Audit_Oct_2021.docx, We got an IP address.
The results obtained from Oletools also confirm that this could be a potential exploit for the CVE-2021-40444 (Microsoft MSHTML Remote Code Execution Vulnerability) vulnerability.
Now let’s dig the rest of challenge files with oleobj
With Employee_W2_Form.docx, We got a domain name.
With Work_From_Home_Survey.doc, We got an URL.
With income_tax_and_benefit_return_2021.docx, We got an another URL.
for futher analysis, you can read it from here
Examing the
Employees_Contact_Audit_Oct_2021.docx file, what is the malicious IP in the docx file?
1175.24.190.249Examing the
Employee_W2_Form.docxfile, what is the malicious domain in the docx file?
1arsenal.30cm.twExaming the
Work_From_Home_Survey.docfile, what is the malicious domain in the doc file?
1trendparlye.comExaming the
income_tax_and_benefit_return_2021.docx, what is the malicious domain in the docx file?
1hidusi.comWhat is the vulnerability the above files exploited?
1CVE-2021-40444Summary#
This challenge was designed for us to gain a basic understanding of MSHTML vulnerability and how we can detect them from Microsoft Office documents.
Badge Acquired