Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e991f8cfd44f78cc…

MALICIOUS

RTF / .DOC

44.8 KB First seen: 2023-06-13
MD5: 191575a3f7a49a90dd83084428435cf1 SHA-1: 6640c716734dc348a210292dedd06d0b06058c70 SHA-256: e991f8cfd44f78cc59c5dae502e2b558575bea0575920624891c3d09ddfee9e5
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 PowerShell

The sample is an RTF document containing an embedded OLE object with data indicative of the Equation Editor vulnerability. The presence of \objdata and \objupdate heuristics strongly suggests exploitation of CVE-2017-11882. The document body contains a lure to enable editing, which is a common tactic for macro-based malware or exploits. The primary goal appears to be executing a second-stage payload via the Equation Editor vulnerability.

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_off0000566e.bin
479726d1e7e6890ee5600bd92f79a8acb415b97e657ac397f40b6e11a1d0aa55
rtf-objdata-decoded RTF \objdata at offset 0x566E 1912 bytes