Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7273339bec4cf789…

MALICIOUS

RTF / .DOC

11.7 KB First seen: 2023-06-13
MD5: 39653abfb913cde974b3b7b87d974c95 SHA-1: a88390c89f55093e27c51b41c0acd48cc43b42af SHA-256: 7273339bec4cf789451c108666b81b2b0f153b1af366102f60caa7b323825f8f
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Phishing: Spearphishing Attachment T1204.002 Malicious File: User Execution

The sample is an RTF document containing an embedded OLE object, specifically targeting the Equation Editor vulnerability. The \objupdate directive forces OLE activation, indicating an attempt to exploit this vulnerability. This exploit likely leads to the download and execution of a secondary payload, typical of a downloader or dropper malware.

Heuristics 4

  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000012a8.bin
0234f297d504636866e2d9d4aac222eb26f7f59ef0bdade00f4d41e9f739237a
rtf-objdata-decoded RTF \objdata at offset 0x12A8 1809 bytes