Malicious RTF — malware analysis report

Static analysis result for SHA-256 20a9c4e061e19bcb…

MALICIOUS

RTF

8.1 KB First seen: 2019-01-20
MD5: 565dc8ca64d7a40b21444b1ef42f16b2 SHA-1: f567fd8b7a7cbc2c68a6750edb2b53b859edaa9b SHA-256: 20a9c4e061e19bcb2ec0300963d4391f1f96a23031d5982c7223e85c34133e88
260 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 triggers the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This vulnerability allows for the execution of arbitrary code, indicating a likely exploit attempt. The presence of the Equation Editor CLSID and the specific vulnerability firing strongly suggest this attack vector.

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_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 4139 bytes
SHA-256: 80b8aa3690560831fdb6b7c957cf1e6c043dacd56f9e9c8d6c6444d16afeed70