Office (OOXML) / .XLSX malware analysis — malicious · fa123a06355ed4c0

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 0ed331fa355fbfe227d58e9b22a1fab8 SHA-1: 2f56f769ccd8fa2035df5aef581f2209b2864907 SHA-256: fa123a06355ed4c00671c98b1cd3636b96f4a651ad5805b63571eea71f73767d

260 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1059.003 Windows Command Shell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The file is an Excel document containing a Workbook_Open macro, which is a common technique for executing malicious code upon opening. The macro attempts to download and execute a batch file from several hardcoded URLs. The obfuscated document body and script content suggest an intent to download and execute a second-stage payload, likely a backdoor or infostealer, as indicated by the ClamAV detection 'Doc.Malware.Valyria-10004384-0'. The script reconstructs several URLs, including 'http://reumatismclinic.com/-/scCnm3mbJRpsaBKbrC/', which are included as IOCs.

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` `d30c843a33f26b1be5bf37474e76e7555fcc0fecf34dea78b629a3b0ccb0e63d`	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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