Office (OLE) / .XLS malware analysis — malicious · 8a7ca24fcbff9d2c

MALICIOUS

Office (OLE) / .XLS

60.5 KB Created: 2023-01-27 15:23:26 Authoring application: Microsoft Excel First seen: 2023-01-27

MD5: 727b412457671a93edb8b7b81e3745cb SHA-1: dabea434b9aa0c84c2f0b6da8e6efceb65bb4c3a SHA-256: 8a7ca24fcbff9d2ce6a0f750628ac40322bc922692e1c6277672105d9e02438b

330 Risk Score

Malware Insights

MITRE ATT&CK

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

The file contains VBA macros that are automatically executed upon opening the workbook via the Workbook_Open event. These macros leverage the URLDownloadToFile API to download a second-stage payload from a remote source, and ShellExecuteA to execute it. The ClamAV detection name 'Xls.Malware.Valyria-10033383-0' 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-10033383-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Malware.Valyria-10033383-0
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.
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)
Suspicious extracted artifact info 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `947ba37e2090c10b0fb7a8dfc5c1a3d4b3943f410c0de4745c84d5f9985a326c`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	16765 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 long base64-like blob(s).

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