Office (OOXML) / .XLSX malware analysis — malicious · 4da71b9da2bf1b08

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: ade7fa9fbd76f9e5125d815182a6bd14 SHA-1: 3e7ddad40d21e5d12010f26c34521f18d5795172 SHA-256: 4da71b9da2bf1b08bfd419d51164124aa2c4264c58b6acb331e3790cb99e426f

260 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1059.003 Windows Command Shell T1204.002 Malicious File T1027 Obfuscated Files or Information

The sample contains a Workbook_Open macro that executes obfuscated commands. These commands appear to download and execute a second-stage payload from multiple URLs, including 'http://reumatismclinic.com/-//scCnm3mbJRpsBKBrc/'. The script also creates batch and VBScript files in the 'C:\programdata\' directory, suggesting an attempt to establish persistence and further execute malicious code. The ClamAV detection 'Doc.Malware.Valyria-10004384-0' further supports the malicious nature of this file.

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` `b549bdcb09ddf9426a2dab01e95fe78d7b93b5ad94e25bf434caa1a6fb9c2119`	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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