Malicious RTF — malware analysis report

Static analysis result for SHA-256 670e3595a0d84f04…

MALICIOUS

RTF

27.3 KB First seen: 2023-07-06
MD5: 637985d77758ae5d69c8990dffe15339 SHA-1: 77a260f8117d464c8b6ec4d6d79464dc89b2d7e8 SHA-256: 670e3595a0d84f046f839aab8e5b316e8f9c6a8f7edf3f39388442863025bca9
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution: Malicious Link T1059.005 PowerShell T1204.002 User Execution: Malicious File

The RTF document contains an OLE object with a split Equation Editor ProgID, indicating an attempt to exploit a known vulnerability. The document body includes a lure instructing the user to 'Enable editing', which, combined with the ".objupdate" directive, suggests the embedded OLE object is designed to activate automatically upon opening. This is likely intended to download and execute a second-stage payload.

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_off00004ff7.bin
21de80c4d2c6ffd8b786e434497987a68f75206da67783aa5ea05f02a5977253
rtf-objdata-decoded RTF \objdata at offset 0x4FF7 1837 bytes