Malicious RTF — malware analysis report

Static analysis result for SHA-256 041faea965203904…

MALICIOUS

RTF

183.5 KB First seen: 2019-01-11
MD5: 686c635fc2260f6e2661c9d8768de29c SHA-1: 35d45c4dd06c73618e1705a18cc0e60fcf32c945 SHA-256: 041faea96520390426f9b0aabaa868daf2c1af07321bc50e55a7757972fe7289
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an RTF document that contains embedded OLE object data, specifically targeting the Equation Editor. Critical heuristics indicate a successful exploitation of CVE-2017-11882, a known vulnerability in the Equation Editor component, which allows for arbitrary code execution. This suggests the file is a malicious attachment likely delivered via spearphishing.

Heuristics 5

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • 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_11882-6934206-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.CVE_2017_11882-6934206-0
  • \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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 58489 bytes
SHA-256: 9f448e1bade90f6d5e14cb47fed87c758b1d6c3212bcfb8ef212b57c543aa088

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