Office (OLE) / .XLS malware analysis — malicious · ecc323c737ea71e8

MALICIOUS

Office (OLE) / .XLS

122.5 KB Created: 2021-10-21 10:31:17 Authoring application: Microsoft Excel

MD5: 643cc6f7df3ef634150217b269afbd8a SHA-1: b66df95d3bb7f48f4d429638ba68219f74f7b079 SHA-256: ecc323c737ea71e81873751995b2c6c5d0bc8845db73466d0d1cdc518c57041b

368 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1105 Ingress Tool Transfer T1059.001 PowerShell

The file contains a Workbook_Open macro that utilizes ShellExecuteA and URLDownloadToFileA. The macro is designed to download a second-stage payload from a remote source and execute it. The presence of these APIs and the auto-execution nature of Workbook_Open strongly suggest a downloader or droppper functionality. The ClamAV detection of Xls.Malware.Valyria-10028013-0 further supports its malicious nature.

Heuristics 9

Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD

Reference to URLDownloadToFile API
URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD

URLDownloadToFile in VBA
ClamAV: Xls.Malware.Valyria-10028013-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Malware.Valyria-10028013-0
Reference to ShellExecute API high SC_STR_SHELLEXEC

Reference to ShellExecute API
Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC

Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
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 macros detected medium OLE_VBA_MACROS

Document contains VBA macro code
Environ() call (env variable access) low OLE_VBA_ENVIRON

Environ() call (env variable access)

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `8b13708fe42363401b7be273404cd6f5f6980fadd8ae61dd730005c8f5790144`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	16300 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 shell/COM execution token(s). Carved artifact contains 20 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.

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