Malicious RTF — malware analysis report

Static analysis result for SHA-256 a94b14e16cac6195…

MALICIOUS

RTF

8.3 KB First seen: 2019-02-26
MD5: d9d90a514547b9f9e1fb7019caaf6641 SHA-1: d81c2fc6b99bcf446abb86ad0d56394c02fae23c SHA-256: a94b14e16cac619550a71e6a6c89c81380e71df3de695eecad7d0ed09f75a109
240 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 indicates an attempt to force the activation of this embedded object, likely leading to the execution of a malicious payload.

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 4137 bytes
SHA-256: a7b71b3514f37ba2a596ba36043c3c332d3cd07468f5cd5af9640bd7f03ceb38