Malicious RTF — malware analysis report

Static analysis result for SHA-256 36731e2892a540d3…

MALICIOUS

RTF

8.2 KB First seen: 2022-03-22
MD5: e0ff9b74bd3cc20dcca8b12b985b0601 SHA-1: 15e3fa4cfb9a42e602e7588d71caefc2158e4d03 SHA-256: 36731e2892a540d3c2c7c8e8121c3f0d9e607dd96c58b7a0ea5b61404647e63a
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The file is an RTF document containing 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 RTF structure and specific heuristic firings strongly indicate this exploit is the primary mechanism for compromise. No scripts were extracted, but the exploit itself is sufficient to deliver a second-stage payload.

Heuristics 4

  • 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.
  • Equation Editor CLSID critical RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • \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_off0000003d.bin
211ec35b8f99c287e8d60b034601f1d78f2cc3c09b4f4fdf55e533c0f3679fd6
rtf-objdata-decoded RTF \objdata at offset 0x3D 4143 bytes