Malicious RTF — malware analysis report

Static analysis result for SHA-256 f9b2eb9ce7da49fc…

MALICIOUS

RTF

8.2 KB First seen: 2020-02-04
MD5: ad5b4a155b81b4e21c5ae8c56258a085 SHA-1: f2cf9967dad86ea55ca71840548d36bbd56944ef SHA-256: f9b2eb9ce7da49fc82836177e640524df20836a98427df72f8ea9fbdc4ffc55f
220 Risk Score

Malware Insights

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

The RTF file contains critical heuristic firings indicating the exploitation of CVE-2017-11882 through an embedded Equation Editor object. The presence of \objupdate further suggests that the embedded object is designed to be activated automatically, leading to arbitrary code execution. This is a common technique for delivering malicious payloads.

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.
  • 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_off00000036.bin rtf-objdata-decoded RTF \objdata at offset 0x36 4147 bytes
SHA-256: a41027aa9fa391c1dfff294ca372d00a9074ab9a5c4bf3b968eedfc9edd87b28