Office (OLE) / .XLS malware analysis — malicious · 8def3f09bd0fae7d

MALICIOUS

Office (OLE) / .XLS

1.39 MB Created: 2016-04-08 13:33:00 Authoring application: Microsoft Excel

MD5: 8f4b05524858cac1f7efa17b9b966856 SHA-1: 7b3aa93c1c69f37161e2e816f9b452320b9cf38c SHA-256: 8def3f09bd0fae7d93db5739af753c88f5e0275eb456f93be5e5c84c4c8ed595

420 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File

The critical OLE_VBA_SHELL and OLE_VBA_WSCRIPT heuristics indicate the VBA macros leverage WScript.Shell to execute commands. The Workbook_Open macro is automatically triggered upon opening the XLS file, suggesting it's designed to download and execute a secondary payload from the URL http://www.frez.co.uk. The SE_PASSWORD_ARCHIVE_LURE heuristic further suggests this is part of a multi-stage attack where the user is prompted for a password to decrypt a payload.

Heuristics 10

Shell() call in VBA critical OLE_VBA_SHELL

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

WScript.Shell usage
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
GetObject call high OLE_VBA_GETOBJ

GetObject 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.

URL http://www.frez.co.uk
Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE

Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
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.

URL http://www.frez.co.uk
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` `3f1bb5f19a8086b2b461561920a09e0f79f19451d1f5aa5464d40b4c40cb67e4`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	1499882 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 shell/COM execution token(s). Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 62 Chr/ChrW string-construction calls. Carved macro source contains an auto-exec entry point and execution/download terms.

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