Malicious RTF — malware analysis report

Static analysis result for SHA-256 a2a91ea17aa275a3…

MALICIOUS

RTF

30.2 KB First seen: 2019-02-26
MD5: c1a028d55b5f467543ae06d3f1fbb124 SHA-1: 8dafcfd485c7fa213d9628d57eeca8f71a251cc1 SHA-256: a2a91ea17aa275a3763565145ae5a65e02c7036c00f22dd8bd6df672d6a7681f
280 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 Equation Editor vulnerability (CVE-2017-11882). This exploit allows for arbitrary code execution, likely to download and run a secondary payload. The ClamAV signature confirms the detection of this specific exploit.

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: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
  • 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_off0000003f.bin rtf-objdata-decoded RTF \objdata at offset 0x3F 15423 bytes
SHA-256: 74524a40ee8f9ff901dfe84ef8c1fec0c337325a14d738a348020e20c0a7f630