Malicious RTF — malware analysis report

Static analysis result for SHA-256 881fe49975983296…

MALICIOUS

RTF

40.0 KB First seen: 2023-07-14
MD5: cff9ecbc256c9828f1e9ea683bc5ea31 SHA-1: 5a4f5465d6efe116d70a2f9186d2be35e2ed3234 SHA-256: 881fe49975983296d63d3a5c39674da11f0b48d1ddc4947b4de2047032b7cc21
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The \objupdate directive indicates that the embedded object will be activated automatically upon opening, which is a common technique for exploiting software vulnerabilities. The document also contains a lure instructing the user to 'Enable editing', further suggesting a malicious intent to bypass security measures and execute an exploit.

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_off00004e0c.bin
ab6046c9d1053c1961e7f3e9eb33b7284024374463e250becab843fb1b8a915d
rtf-objdata-decoded RTF \objdata at offset 0x4E0C 1682 bytes