Malicious RTF — malware analysis report

Static analysis result for SHA-256 b3526a8d75d3806c…

MALICIOUS

RTF

261.2 KB Created: 2018-07-03 09:28:00 First seen: 2021-01-23
MD5: 4fc3362c7d363b96d22971e564d4339d SHA-1: 45bda897474ac4d7e5b3b8f7c9e8be5131505d75 SHA-256: b3526a8d75d3806c761fc61f9e2845188b85fe0db82d1d4218d9c0cdcd70ae05
262 Risk Score

Heuristics 7

  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • ClamAV: Doc.Exploit.Cve_2017_11882-7570663-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.Cve_2017_11882-7570663-1
  • Equation Editor shellcode downloads a second-stage payload critical OLE_MTEF_SHELLCODE_DOWNLOAD_URL
    The shellcode reached by the Equation Editor overflow resolves download/exec APIs (URLDownloadToFile / ShellExecute / WinExec) and fetches a second-stage payload. The download URL was recovered from the Equation Native stream — directly when the shellcode is plaintext, or by emulating its self-decoding stub. An integer-encoded host (e.g. http://000030000706151) is normalised to its dotted-quad form and both spellings are surfaced as IOCs.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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 https://cheapjerseysangels.com/1/wyyeok.msi In RTF body
    • http://000030000706151In RTF body
    • http://192.3.140.105Decoded from obfuscated IP host (000030000706151)
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000bf6b.bin rtf-objdata-decoded RTF \objdata at offset 0xBF6B 15672 bytes
SHA-256: fbad6b720fea3003d446210e2190307b87a95f06ad5e5955d900b3cf28d2670b