Malicious RTF — malware analysis report

Static analysis result for SHA-256 1fbae28b576c307f…

MALICIOUS

RTF

2.03 MB First seen: 2026-06-05
MD5: 5f6b306a19fec9bcb9f1090f1dbdc539 SHA-1: a2dafa04b105eddfe80f3935af95c739b9e99a9a SHA-256: 1fbae28b576c307f28b63c180f80cdc8a081093dfe6d83f58ea1e688839e8db7
220 Risk Score

Malware Insights

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

The RTF document contains embedded OLE object data, specifically related to Equation Editor. Critical heuristics indicate a likely exploitation of CVE-2017-11882, which is known to be used for client-side execution of arbitrary code. The presence of a large, hex-encoded payload within the OLE object further supports this. The document likely functions as a spearphishing attachment designed to exploit this vulnerability.

Heuristics 5

  • Split hex Equation Editor ProgID + OLE object critical CVE likely RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
  • \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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~2131KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000007c.bin rtf-objdata-decoded RTF \objdata at offset 0x7C 852908 bytes
SHA-256: 88d08ec54cf5dba88b2cfe72aeade4720d9ad4189f8b29b92682cfe5c53e3953

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