Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 9290d8425cedb9ab…

MALICIOUS

RTF / .DOC

16.2 KB First seen: 2023-03-16
MD5: 361dc7fad286ccc5331aa30b58152316 SHA-1: 74f0ab3f43ef20e9af3b9660795bd8f0efb5c17e SHA-256: 9290d8425cedb9aba9f1d216aac607f531c7a704b281bf7be590baec45ce3583
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object, specifically targeting the Equation Editor vulnerability. The presence of \objupdate indicates an attempt to automatically activate the embedded object upon opening. The document body contains a lure instructing the user to 'Enable editing', which is a common tactic to bypass macro security and trigger the exploit. The exploit likely leads to the download and execution of a second-stage payload.

Heuristics 4

  • 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 1 \objdata section(s) — embedded OLE objects
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000024ab.bin
7b5a23a55324136ead93b0f822d3bef13086532cab2f2f7ffa7057ca67d001f9
rtf-objdata-decoded RTF \objdata at offset 0x24AB 1581 bytes