equation editor exploit — RTF malware analysis

Static analysis result for SHA-256 f96bf4dbaeb47359…

MALICIOUS

RTF

7.2 KB First seen: 2019-05-31
MD5: 1fbe70bca46e3b52e5de10734d4a32df SHA-1: 7be7ae41582102b0d2050344698411648cae48d5 SHA-256: f96bf4dbaeb4735968637a3666c25fa3df0234695b90d65aabb07f38248bb3ac
180 Risk Score

Malware Insights

equation editor exploit · confidence 95%

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

The RTF file contains embedded OLE object data and specifically triggers heuristics for CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. This indicates the file is designed to exploit this vulnerability for client execution. The presence of the ".objupdate" directive further suggests an attempt to activate the embedded OLE object, likely to trigger the exploit. The file is therefore classified as an exploit document, likely delivered via spearphishing.

Heuristics 4

  • 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.
  • \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_off00000032.bin rtf-objdata-decoded RTF \objdata at offset 0x32 3642 bytes
SHA-256: 351a1499b792347c7b00838262caf1e749f35e654c6219ecbe22064c6d532f6b

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