Valyria Office (OLE) / .XLS malware analysis — malicious · 841dc15f639ce1e1

MALICIOUS

Office (OLE) / .XLS

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

MD5: 5ab70e584a81cf21b48decbe182d5b2a SHA-1: 92277b07d380c129ed65fad79ff5c13eb7b51650 SHA-256: 841dc15f639ce1e1a4ffedc8529795dcebc29619cd4a7810433235c1049ea8ff

400 Risk Score

Malware Insights

Valyria · confidence 70%

MITRE ATT&CK

T1204.002 User Execution: Malicious File T1059.005 Command and Scripting Interpreter: Visual Basic for Applications

The sample is an Excel file containing VBA macros that are configured to auto-execute via the Workbook_Open event. The script is heavily obfuscated with large arrays of numeric values, making the exact payload delivery mechanism (e.g. a specific URL) unreconstructable from the truncated script excerpt. However, ClamAV explicitly identifies this as Valyria malware. The use of Shell() and WScript.Shell via CreateObject is consistent with the same family's behavior of dropping and executing a second-stage payload.

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` `93e11b7f3b44fef97a980e1806b01ad64dd1e1e656af5571d46c2fb0ffe8fdcd`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	34225 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 shell/COM execution token(s). Carved artifact contains 69 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.

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