Office (OOXML) / .XLSX malware analysis — malicious · a36aaa499b8fc2b0

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: e4857042448e3edacf7f577b7eac207a SHA-1: b5ef2692e64e40012dd5ff93bf7addef3ff4249c SHA-256: a36aaa499b8fc2b081bf524c321fe184ac0755bdca2c0cf066057ea836f4f493

260 Risk Score

Malware Insights

MITRE ATT&CK

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

The file is an Excel document containing a Workbook_Open VBA macro, which is a common technique for executing malicious code upon opening. The macro attempts to download and execute a second-stage payload from several URLs, including 'http://reumatismlinica.com/--/scCn m3mbJRpwB KbrC/'. It also writes a batch file to 'c:\programdata\jledshf.bat' and a VBScript to 'c:\programdata\sduoixo.vbs', likely for execution or further payload delivery. ClamAV detections further confirm 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` `8de604a256b2eab48e95b806ce00a94b9dd6bb53505a80e5701b62d4c88c41c6`	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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