Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7fb33351d6ef6a9a…

MALICIOUS

RTF / .DOC

63.1 KB
MD5: 85f32390c19a033a1d2569863469a615 SHA-1: 81689cd34e0ad021432bd0db43f5313cf0189705 SHA-256: 7fb33351d6ef6a9ae6f3c953b3c45743281217ed32c7fe8ef8d9f06161589e7d
120 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document that contains embedded OLE objects, specifically triggering heuristics related to the Equation Editor vulnerability. The \objupdate heuristic indicates that the embedded object is designed to be activated automatically. This suggests the document is a lure designed to exploit the Equation Editor vulnerability to gain initial access and likely download a secondary payload.

Heuristics 3

  • 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000af9.bin
621fa5b90709da6111801e73311ed97be8a8a35b9d58206641974af6641930e7
rtf-objdata-decoded RTF \objdata at offset 0xAF9 1618 bytes