Valyria Office (OLE) / .XLS malware analysis — malicious · abfbf608cf5cd1e1

MALICIOUS

Office (OLE) / .XLS

653.0 KB Created: 2018-12-06 20:43:11 Authoring application: Microsoft Excel

MD5: b26c5f3aaf4caf613dceabd8fc9de3b7 SHA-1: 0e375948ee81056cd109c998cfcb4a6419cb1954 SHA-256: abfbf608cf5cd1e1ed75f1f552dc04785c509a75586d26ec51d39b45694c555d

400 Risk Score

Malware Insights

Valyria · confidence 85%

MITRE ATT&CK

T1204.002 User Execution: Malicious File T1059.005 Command and Scripting Interpreter: Visual Basic for Applications T1059.003 Command and Scripting Interpreter: Windows Command Shell T1569.002 System Service: Windows Command Shell

The sample is an Excel workbook containing a Workbook_Open macro that automatically executes upon opening. The VBA script is heavily obfuscated using a large array of numeric values, which is typical of downloader behavior. ClamAV detection as 'Xls.Malware.Valyria' directly supports the family attribution. The script uses Shell() and WScript.Shell via CreateObject to execute commands on the host system, though the final payload URL or command line was too obfuscated to reconstruct from the truncated script excerpt.

Heuristics 9

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
WScript.Shell usage critical OLE_VBA_WSCRIPT

WScript.Shell usage
ClamAV: Xls.Malware.Valyria-10032137-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Malware.Valyria-10032137-0
Reference to Windows Script Host high SC_STR_WSCRIPT

Reference to Windows Script Host
Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
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

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `776cfaaaeb53f69ce6b02c2227bec0ef4bfccdc6a706ca12656b68d14212beb3`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	110311 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 shell/COM execution token(s). Carved artifact contains 211 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.

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