Malicious Office (OLE) / .DO — malware analysis report

Static analysis result for SHA-256 5da012d4eec5e3d2…

MALICIOUS

Office (OLE) / .DO

139.9 KB Created: 2005-06-29 18:14:00 Authoring application: Microsoft Word 10.0
MD5: 933e00dd29f9f1f2311bd508e8bcaf43 SHA-1: a7f87bd0662409d3dc37c09561721f424d7f7952 SHA-256: 5da012d4eec5e3d272f04dca02d0eb758d9fc19350ce6099ab20471adc7982af
742 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.003 Windows Command Shell T1105 Ingress Tool Transfer

The sample is a malicious OLE document exploiting CVE-2008-2244 to drop and execute an embedded PE file. Heuristics indicate the use of CreateProcess, WriteProcessMemory, and CreateRemoteThread, suggesting the embedded executable is likely a downloader. Suspicious cmd.exe invocation and embedded URLs further support this. ClamAV detection confirms the malicious nature.

Heuristics 17

  • CVE-2008-2244 — Microsoft Word record-parsing payload critical CVE likely CVE_2008_2244
    Word OLE document has normal small WordDocument/table streams, a large unallocated OLE slack region, and an executable or resolver shellcode payload in that slack. This is the static shape of the MS08-042 Word record-parsing exploit family tracked as CVE-2008-2244.
  • Reference to WriteProcessMemory API critical SC_STR_WRITEPROCESSMEMORY
    Reference to WriteProcessMemory API
  • Reference to CreateRemoteThread API critical SC_STR_CREATEREMOTETHREAD
    Reference to CreateRemoteThread API
  • Embedded PE executable critical OLE_EMBEDDED_EXE
    MZ/PE header found inside document — possible embedded executable
  • ClamAV: Win.Downloader.97183-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Downloader.97183-1
  • 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.
  • x86 GetPC stub (CALL $+5; POP EAX) high SC_GETPC_CALL
    x86 GetPC stub (CALL $+5; POP EAX)
  • PEB access via FS segment (x86) high SC_PEB_ACCESS
    PEB access via FS segment (x86)
  • PEB API-hash resolver high SC_API_HASH_RESOLVER
    PEB access followed by ROR13-style API hashing, a common position-independent shellcode import resolver
  • Reference to CreateProcess API high SC_STR_CREATEPROCESS
    Reference to CreateProcess API
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • Reference to GetProcAddress API high SC_STR_GETPROCADDRESS
    Reference to GetProcAddress API
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 143,265 bytes but its declared streams total only 20,632 bytes — 122,633 bytes (86%) live in unallocated sector slack. This is the canonical hiding place for pre-macro-era Office exploit payloads (XOR-encoded shellcode reached via a parser pointer-corruption bug in the document structure).
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • 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://%s:%d/net/B%s/search%s.php
    • http://%s:%d/net/B%s/serinfo
    • http://about:blank
    • http://www.google.cn/images/nav_logo3.png

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_office_0000f39d.exe
bfd140a2f831bb83245be73301b5cca2868cd056149fa2cab4f99838b4ec0925		 embedded-pe Office MZ+PE at offset 0xF39D 80900 bytes
Detection
ClamAV: Win.Downloader.97183-1
Obfuscation or payload: unlikely

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