Office (OOXML) / .XLSX malware analysis — malicious · b9ef57c27f2664d9

MALICIOUS

Office (OOXML) / .XLSX

111.6 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 12.0000

MD5: 580d6ac855923b9b9e1443a287a38b78 SHA-1: 8d9c499397ca2bb837fc0a2cf61b6c5a2d262804 SHA-256: b9ef57c27f2664d9bfdf38547bfd6d5084513827e16bfb387a1d6ffde4397a29

260 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The sample is an Excel document containing a Workbook_Open macro, identified by the OLE_VBA_WBOPEN heuristic. This macro is designed to download and execute a secondary payload. The obfuscated DOC BODY and the VBA script indicate the intent to run a batch file and a VBScript from the \"c:\programdata\" directory. The script attempts to reconstruct a URL from concatenated strings, which resolves to 'http://reumatismclinic.com/-//scCn3mbJRPsBKBrc/', among others, likely for downloading the initial payload. The ClamAV detection further confirms its malicious nature.

Heuristics 6

ClamAV: Doc.Malware.Valyria-10004384-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Doc.Malware.Valyria-10004384-0
ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV

ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
Suspicious extracted artifact high 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.
VBA project inside OOXML medium OOXML_VBA

Document contains vbaProject.bin — VBA macros present

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `527d0656a0c2c323955d068683ef8f7e20c035cda247a1e24383595c0eb3403b`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	7821 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved macro source contains an auto-exec entry point and execution/download terms.
`vbaProject_00.bin` `4789297a1c13b8b366aa4d9e02eda7ebc82e3a1965e62d658bbf4353529feae8`	vba-project	OOXML VBA project: xl/vbaProject.bin	37888 bytes
Detection ClamAV: Doc.Malware.Valyria-10004384-0 Obfuscation or payload: likely Carved macro source contains an auto-exec entry point and execution/download terms.

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