Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 71c40fb6bbdf132d…

MALICIOUS

RTF / .DOC

19.2 KB
MD5: fc737fc30f8ea359be13bb354d75a786 SHA-1: af52125ae3502d6a1881f9e97e090843920e2c37 SHA-256: 71c40fb6bbdf132d2f42c5ccd773543d7f0a96bd0ae3527ab2f27dc3fec23ae5
120 Risk Score

Malware Insights

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

The sample is an RTF document that contains embedded OLE objects and triggers an Equation Editor vulnerability. This exploit is designed to execute arbitrary code, likely to download and run a secondary payload. The presence of ".objdata" and ".objupdate" sections further indicates the use of embedded objects for exploitation.

Heuristics 3

  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000d3d.bin
2a38120a10c76e8089edd5a705a9cf6c30a946817cf9ddfb892966c3ea490f26
rtf-objdata-decoded RTF \objdata at offset 0xD3D 1662 bytes