Jrat — Office (OLE) malware analysis

Static analysis result for SHA-256 b56285ce43b1934b…

MALICIOUS

Office (OLE)

1.36 MB Created: 2021-07-15 09:57:00
MD5: b2a7e405503858e1e6f8ec093e50d8e5 SHA-1: afd698cb46334da3aabf417befdf4ba2611b2d00 SHA-256: b56285ce43b1934bdabdd4fac12e368d5464eb5654afa87979221ba477fa350d
642 Risk Score

Malware Insights

Jrat · confidence 95%

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 Visual Basic T1027 Obfuscated Files or Information T1105 Ingress Tool Transfer

The sample is identified as malicious by ClamAV with the signature Doc.Downloader.Jrat-6336393-1. It exploits CVE-2007-3899, a known vulnerability in Microsoft Word, to execute embedded VBA macros. The Document_Open macro is designed to download and execute a second-stage payload, likely an embedded PE executable, using ShellExecuteA. The macro also attempts to obfuscate its actions and uses a reconstructed string for execution.

Heuristics 16

  • CVE-2007-3899 — Microsoft Word malformed string memory corruption critical CVE likely CVE_2007_3899
    Word OLE document has the MS07-060 malformed-string exploit shape: a Word 97-family FIB points to a malformed DOP/string-table region with an abnormal INT_MAX run, inflated text counters, and exploit payload or Mdropper.Z campaign evidence.
  • Office EPRINT stream contains EMF object high CVE related OLE_EPRINT_EMF_OBJECT
    OLE ObjectPool contains an EPRINT stream with EMF data. This is rare in normal documents and is CVE-2007-3893/MS07-046-family evidence when paired with Office exploit payload anomalies, but the malformed EMF record is not proven by this rule alone.
  • OLE with Ole10Native — possible CVE-2026-21514 exploitation high CVE likely CVE_2026_21514
    Document contains a Word OLE object with Ole10Native plus executable, PE, or risky remote-link indicators. CVE-2026-21514 exploits OLE metadata validation; this stronger structure is treated as likely exploitation.
  • Embedded PE executable critical OLE_EMBEDDED_EXE
    MZ/PE header found inside document — possible embedded executable
  • ClamAV: Doc.Downloader.Jrat-6336393-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Jrat-6336393-1
  • 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.
  • Reference to WinExec API high SC_STR_WINEXEC
    Reference to WinExec API
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • Reference to GetProcAddress API high SC_STR_GETPROCADDRESS
    Reference to GetProcAddress API
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • Ole10Native package carries executable/script file type high OFFICE_PACKAGE_RISKY_FILE
    OLE Package displayName or fullPath ends in an executable or script-capable extension. Even without UI extension spoofing, embedding a runnable payload inside an Office document is a high-risk delivery pattern.
  • 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.
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • 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://schemas.openxmlformats.org/drawingml/2006/main

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
e3369546294f4e81ce018004ba8d9ab604e8f490a4b044d291a9ba95eae7fd70		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 3258 bytes
embedded_office_0008fc6e.exe
3de5690cf40ad51d92650cd9ca118ed2ce03930958919f1b8e576dce15bd24e4		 embedded-pe Office MZ+PE at offset 0x8FC6E 832914 bytes
Detection
ClamAV: Win.Packed.Zusy-9878765-0
Obfuscation or payload: unlikely
ole10native_00.bin
fa257924db9ef22f489d6ca146d5e6ece65c8cd39ed11d63a694634d1e79a7c6		 ole-package OLE Ole10Native stream: ObjectPool/_1687823081/Ole10Native 792364 bytes

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