Malicious RTF — malware analysis report

Static analysis result for SHA-256 1f41b24d586e1682…

MALICIOUS

RTF

7.4 KB First seen: 2019-08-04
MD5: 79d39160ba2d30d6ce1df64f7d615993 SHA-1: c9c1272fe99a1c7559040ca17e12c2aa140b74ad SHA-256: 1f41b24d586e16821df0749c49e62575693334954277544622c64849aa25fdb9
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE object data and specifically triggers heuristics related to Equation Editor and CVE-2017-11882. This indicates the file is designed to exploit this vulnerability for client-side execution. The presence of ".objupdate" further suggests an attempt to force OLE object activation. No specific family could be identified, but the exploit vector is clear.

Heuristics 5

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • ClamAV: Doc.Exploit.CVE_2017_11882-6934206-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.CVE_2017_11882-6934206-0
  • \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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000033.bin rtf-objdata-decoded RTF \objdata at offset 0x33 3631 bytes
SHA-256: 15315b008e8b2522ec8a6f0dba3be171b35fc11e7ee2d6315474b1f1d354e5a4