Malicious RTF — malware analysis report

Static analysis result for SHA-256 5c881806adca508a…

MALICIOUS

RTF

4.4 KB First seen: 2019-08-04
MD5: d203e5a25ec406a28f78f709797a44f9 SHA-1: d96d3c251cdf838eff0aabed6d0b800da25c6fda SHA-256: 5c881806adca508ac264b66a5cde4c8cbb11d8b6479b0350b647f4e65c6bde71
180 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for arbitrary code execution when the object is activated, likely leading to the download and execution of a secondary payload. The specific ProgID 'EquATiOn.3' is indicative of this exploit.

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 activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger 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.
  • 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_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 2219 bytes
SHA-256: 04f88dd94bdf07e876766a0ecd8b072664f9399026f253b0dc8e44dcd0baaaf9

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