Office (OOXML) / .XLSX malware analysis — malicious · b84c0e38f1a3beba

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 1bc9b742ace17be9454b18d7510ba77b SHA-1: 5db0460ab3cb9237974727f6c76172f6ef2ceff3 SHA-256: b84c0e38f1a3beba4c500955dc98faf0b8484e879ddd6930b95f82da250cf78f

260 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample is an Excel document with a Workbook_Open macro that executes a batch file and a VBScript. The batch file is constructed from concatenated variables, including a command to execute a VBScript located at 'c:\programdata\sduoixo.vbs'. The VBScript itself is heavily obfuscated but appears to be responsible for downloading and executing additional payloads from several hardcoded URLs. The ClamAV detection 'Doc.Malware.Valyria-10004384-0' further confirms its malicious nature. The primary intent appears to be the execution of a second-stage payload via the embedded scripts.

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` `a60b4727d8f22798619ff58d7bff3b428d63d03a3788a244b2e7fafcbe109f61`	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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