Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c46ce29d50340889…

MALICIOUS

RTF / .DOC

33.2 KB First seen: 2023-01-13
MD5: 0948ac21b8c2b37c95b5f6953c537333 SHA-1: b33bd9e8f4fe66e3586e9d2d9e5c4a4ee83ce83d SHA-256: c46ce29d5034088998506ea42aef07ab34c742f64a727524fe8696e32c66d499
200 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object specifically identified as related to the Equation Editor vulnerability, CVE-2017-11882. The presence of \objupdate and the specific ProgID 'eqUATiOn.3' strongly indicate exploitation of this known vulnerability. The document body contains a lure instructing the user to 'Enable editing', a common tactic to bypass security measures and trigger the exploit. The primary goal is to execute a secondary payload.

Heuristics 6

  • 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.
  • Split hex Equation Editor ProgID + OLE object critical 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.
  • \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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000468b.bin
c0ea9621e1b3a515874107300d3ba54214ff80fb42de2082ec87634086a0946d		 rtf-objdata-decoded RTF \objdata at offset 0x468B 1801 bytes

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