Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 c58e6ea986c09908…

MALICIOUS

Office (OOXML)

26.5 KB Created: 2021-08-18 02:04:39 UTC Authoring application: Microsoft Excel 16.0300
MD5: c81b78c33a7822aba5d4af58107d1034 SHA-1: 355a9fe6f59db67bac91b4eb1914022b1ae759af SHA-256: c58e6ea986c0990865471f98f35c59c9296100b3d558f7f700b411779342c183
610 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is an Excel document containing a VBA macro with an Auto_Open subroutine. This macro utilizes WScript.Shell and WMI (Win32_Process.Create) to download a second-stage payload from the URL http://ec2-18-184-17-12.eu-central-1.compute.amazonaws.com/standardchartered/passleak/180821/ and save it to disk as Details.dat and LeakDetails.dat in the temporary directory. The macro also attempts to execute this downloaded file.

Heuristics 14

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • Obfuscated VBA Shell command with URL critical OLE_VBA_OBFUSCATED_SHELL_URL
    VBA macro invokes Shell with command text assembled through decoder or string-manipulation functions and includes a URL. This is a high-confidence downloader/dropper pattern, stronger than Shell or URL evidence on their own.
  • VBA WMI Win32_Process launcher critical OLE_VBA_WMI_PROCESS_CREATE
    VBA macro builds or references a WMI moniker for Win32_Process and invokes .Create to start a command. This is a high-confidence macro execution chain that often hides the WMI class name through string concatenation or helper functions.
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
  • ClamAV: Doc.Downloader.Valyria-10026858-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Valyria-10026858-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_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.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://ec2-18-184-17-12.eu-central-1.compute.amazonaws.com/standardchartered/passleak/180821/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
a8f9df169933129720afb1f5adce4921c37b61c6520135a17603c1814a172261		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 4717 bytes
vbaProject_00.bin
4d0e28223232cb8055bef97acabd7917556aa30f6b8063d3c218c45460a56739		 vba-project OOXML VBA project: xl/vbaProject.bin 18432 bytes
Detection
ClamAV: Doc.Downloader.Valyria-10026858-0
Obfuscation or payload: unlikely

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