Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 663d9579abbd1942…

MALICIOUS

RTF / .DOC

1.81 MB
MD5: be5f1f0e54e923bcc73b3bd3bae6c265 SHA-1: efd01b61e424cde908465599f1c431deea1d54d1 SHA-256: 663d9579abbd19429c05c5c2c66ed7a83df6d78c91cc4d60069156e27f207391
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 the Equation Editor vulnerability (CVE-2017-11882). This exploit is designed to execute arbitrary code, likely a second-stage payload, upon activation. The presence of excessive hex-encoded data within the OLE object further suggests the hiding of malicious content.

Heuristics 5

  • 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.
  • 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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1900KB 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_off0000009a.bin
949dd36cbb9480c431042c8f7c77a326ef5090d1e96e1f2f1c0d83f42d88bd9b		 rtf-objdata-decoded RTF \objdata at offset 0x9A 950384 bytes

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