Malicious RTF — malware analysis report

Static analysis result for SHA-256 93b4a7cf5b5de6ea…

MALICIOUS

RTF

8.3 KB First seen: 2019-05-31
MD5: e71542a38190a72a8c19dcf592dfc465 SHA-1: 462616fddd2c8b1827478dadc946663c9a555a58 SHA-256: 93b4a7cf5b5de6ea71092b2843480596122904a20de834a181c27bbeb67aecfe
260 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 critical heuristics for the Equation Editor CLSID and CVE-2017-11882. This indicates the file is designed to exploit a known vulnerability in Microsoft Equation Editor to achieve code execution. The presence of ".objupdate" further suggests an attempt to force OLE object activation. The file is classified as malicious due to this exploit.

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.
  • 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000032.bin rtf-objdata-decoded RTF \objdata at offset 0x32 4138 bytes
SHA-256: 34336a32df6175b95a3edbbfa7a8ad789cc8f6d5c2c81c99cd9bfaa58974caf1

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