Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8a9dab92f875ec4a…

MALICIOUS

RTF / .DOC

27.4 KB First seen: 2022-11-14
MD5: 3adc90c6573db0fab6dbfb4713955669 SHA-1: 68779c2df54ffc2edd95e24c920c194aeafcaae2 SHA-256: 8a9dab92f875ec4ac1bbb346974829a0948e859819294ec37c44e8c565898fb4
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. The presence of \objupdate indicates an attempt to automatically activate this object upon opening. The document body contains a lure instructing the user to 'Enable editing', a common tactic to bypass macro security and trigger the exploit. The exploit likely leverages a known vulnerability in the Equation Editor to execute a malicious 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_off00005a77.bin
47f6df7c29c6350b14d07f0adc4c74a80266cfb41dc38e3a7400838606d554ab
rtf-objdata-decoded RTF \objdata at offset 0x5A77 1378 bytes