Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 22a5519a921481a0…

MALICIOUS

RTF / .DOC

32.1 KB First seen: 2023-05-22
MD5: c3681f1d0664c277cec547bd6f1824ef SHA-1: 91d1b3bb71bf0e1d80c1c7b36eabe5300743389c SHA-256: 22a5519a921481a059e0dda9325b40aa6e0a7709a0b969d3821a26bed2753b89
140 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The document body includes a lure instructing the user to 'Enable editing' to view the content. The presence of RTF_OBJDATA and RTF_OBJUPDATE heuristics further indicates the exploitation of OLE object activation. This combination strongly suggests an exploit delivery mechanism for the Equation Editor vulnerability.

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_off000040b5.bin
f8c6b15f6b97575340e4385d02db00a4c42a38124f70a4bf8fe873a8b9c307d6
rtf-objdata-decoded RTF \objdata at offset 0x40B5 1503 bytes