Malicious RTF — malware analysis report

Static analysis result for SHA-256 5387e2bd608c6817…

MALICIOUS

RTF

8.4 KB First seen: 2019-09-30
MD5: 920b8022cf38fb202b76f11fe9844e73 SHA-1: fdb47ea5bfc0bafb2cc80cf236b485cb1f866cec SHA-256: 5387e2bd608c6817eb35e58b962c75e8c9ba2bc2351035428351f714eb1ff621
220 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This vulnerability allows for arbitrary code execution when the object is activated. The presence of the ".objupdate" directive further suggests an attempt to force the activation of this malicious object.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off00000036.bin rtf-objdata-decoded RTF \objdata at offset 0x36 4147 bytes
SHA-256: 3944eddcca99da8d4df4f3e504fcaee1702ed17eac64cbd729660bdbd6e69e42