Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 4b8c610c5e83b3b4…

MALICIOUS

RTF / .DOC

30.9 KB First seen: 2023-06-17
MD5: 15946e09f89d472e175a626f3b8e314c SHA-1: 500af3c6a90cb82ce346566b7ef7661cc3cb0eb0 SHA-256: 4b8c610c5e83b3b4f231233c642d3d9bef476012d4c77eaf3bcfe5a7212abacd
140 Risk Score

Malware Insights

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

The sample is an RTF document containing 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, which is a common tactic for macro-based malware droppers. The presence of RTF_OBJDATA and RTF_OBJUPDATE heuristics further supports the exploitation of embedded OLE objects.

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_off00005428.bin
2fb916e94307860e1cb37b0168fb10df7a05a0a8ba0b783356dc05fcef2203b3
rtf-objdata-decoded RTF \objdata at offset 0x5428 1829 bytes