Malicious RTF — malware analysis report

Static analysis result for SHA-256 a9d288724ac81d55…

MALICIOUS

RTF

8.1 KB First seen: 2019-01-20
MD5: 17196724829b248438f1aa5ce2c8008b SHA-1: 39a6ef7842c851791fd2075adf3022728a073d9e SHA-256: a9d288724ac81d55c5d26b00dafb6cf585de16a15e4218bad2b2bf33973e1c7e
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 the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for the execution of arbitrary code when the embedded object is activated, likely via an ".objupdate" directive. The file is detected by ClamAV as Doc.Exploit.CVE_2017_11882-6934206-0, confirming the exploit attempt.

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_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 4132 bytes
SHA-256: d33321c480e066fe16edc9491c6394e7e91231ac3d37a17745d84aed1a49929f