Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 213b07abf38bbc53…

MALICIOUS

RTF / .DOC

3.9 KB First seen: 2022-08-16
MD5: 713dfb352d680d0310d9eeb0101019c3 SHA-1: 41520e7bc53e9c870c3c9ecd0c0fa556ff30e7cf SHA-256: 213b07abf38bbc53fa6559b0800e2a68b9e7e5d94962c6c35b9ff2207ebbcfbc
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains embedded OLE object data and triggers an objupdate event, indicating exploitation of the Equation Editor vulnerability (CVE-2017-11882). This technique is commonly used to deliver a second-stage payload. No specific family could be identified, but the exploitation method is clear.

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_off00000070.bin
fcf825d9b8cb49c1d280869ca68a02df6a53e7c4ce21703daa828e4d21d31908
rtf-objdata-decoded RTF \objdata at offset 0x70 1624 bytes