Malicious RTF — malware analysis report

Static analysis result for SHA-256 3aa9c9cf6ed34ecb…

MALICIOUS

RTF

261.1 KB Created: 2018-07-03 09:28:00 First seen: 2020-05-14
MD5: bab269b9c618244089cc076e1ecb1e20 SHA-1: 9c1ae6c097ee0f41f516d3b04060bd3e465eccb9 SHA-256: 3aa9c9cf6ed34ecb67fecc41d2e0d54835fe277fed876e1a1dc3e85eed2c0396
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 http://auto-klad.ru/wp-includes/Requests/css/l/scob.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: 849d1556d9dd87162983ada07cc7b010e29adea85a77d01dada6cb4063cf39d0