Malicious RTF — malware analysis report

Static analysis result for SHA-256 cb31b806bd8ba3ee…

MALICIOUS

RTF

8.3 KB First seen: 2019-06-27
MD5: eca2656e9d032ba26c1ff6d73a61d2d6 SHA-1: b9aa3ec753b30794d80f214466c70cdca636a23a SHA-256: cb31b806bd8ba3eeeb19617e62de96b2ed1e81df55eb995eed7bb5797dab5d6e
260 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits CVE-2017-11882 via Microsoft Equation Editor. This vulnerability allows for arbitrary code execution, indicating the file's primary purpose is to exploit this known flaw. The ClamAV detection further confirms its malicious nature as an exploit document.

Heuristics 6

  • 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000032.bin rtf-objdata-decoded RTF \objdata at offset 0x32 4147 bytes
SHA-256: e5174d3dc4e5904cac1b177da01d1fb418a83ddba1c438eb1104249770a0ccc3