Malicious RTF — malware analysis report

Static analysis result for SHA-256 d040c85b30bbd2ca…

MALICIOUS

RTF

43.6 KB First seen: 2023-07-19
MD5: d8b399efb97cc74e226421ebcd69c765 SHA-1: 5521553b5dce6892e4afaf3f6e6cacca5e3972ad SHA-256: d040c85b30bbd2caf9db04bde4605cfbf6fc5f3e9e3aa27ad6aa115721d47137
160 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object and specifically triggers heuristics related to Equation Editor vulnerabilities and OLE object activation. The document body includes a lure instructing the user to 'Enable editing', a common tactic for macro-based malware. The presence of these indicators strongly suggests an exploit targeting the Equation Editor to achieve code execution, likely for a downloader.

Heuristics 5

  • 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off00005879.bin
a66547ee583723aa477a0fb9544ca6ae59a6660a002e61a3d2a3c4b94f7f6ff9
rtf-objdata-decoded RTF \objdata at offset 0x5879 1683 bytes