Malicious RTF — malware analysis report

Static analysis result for SHA-256 c9ef81d46f795dff…

MALICIOUS

RTF

9.1 KB First seen: 2019-04-17
MD5: 88e4acfc0131677fd96aa005ddd6d6bb SHA-1: 675bac32515d97aa1581914c49ae353a8489fb5e SHA-256: c9ef81d46f795dfff34f9200ec609372af2ccf80717d8aca6a9b4bc4ce561302
280 Risk Score

Malware Insights

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

The RTF file contains embedded OLE object data and specifically triggers heuristics related to CVE-2017-11882, a known vulnerability in the Equation Editor component. This exploit allows for arbitrary code execution, which is typically used to download and run a second-stage malicious payload. The ClamAV detection further confirms the malicious nature of the file, identifying it as Doc.Exploit.CVE_2017_11882-6934206-0.

Heuristics 6

  • 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.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • 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_off0000003c.bin rtf-objdata-decoded RTF \objdata at offset 0x3C 4644 bytes
SHA-256: 351fbd647975bad29ae5f845d640ee923506aa982df43ce47f3db73e9c59f2e3

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