Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 3dc8800e380890fe…

MALICIOUS

RTF / .DOC

33.9 KB First seen: 2023-03-30
MD5: db36641ec3f10d09764c30c7b5b878f4 SHA-1: 0a743acaa85fa32457e6a84dfc1dbab53cd07495 SHA-256: 3dc8800e380890fec915d4f62026caf4c5ff66f409d1c305c27b5f0ea14834b5
140 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with a specific Equation Editor ProgID, and an \objupdate directive that forces its activation. This strongly suggests an attempt to exploit a known vulnerability, such as CVE-2017-11882, through a malicious attachment. The document body's lure to 'Enable editing' further supports this attack vector.

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
  • 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_off0000586a.bin
6aa9c32e464d6e17560f67ced7c6832ab7362a2c2f541240bbe099fe09189b31
rtf-objdata-decoded RTF \objdata at offset 0x586A 1528 bytes