Malicious RTF — malware analysis report

Static analysis result for SHA-256 9fd787f18cf4ed30…

MALICIOUS

RTF

96.1 KB First seen: 2024-10-06
MD5: 93033dda218831cdb2db14b3d7ce18f3 SHA-1: 37543dcb44c66dd57c488378303049f2df75090c SHA-256: 9fd787f18cf4ed3034e22402afd212375507e9d0f89dd7b10d8ce36110ca8977
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The ".objupdate" directive indicates that the OLE object is automatically activated upon opening the document, leading to the exploitation of the Equation Editor. This technique is commonly used to achieve arbitrary code execution, typically for downloading and executing a second-stage payload.

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 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000113c.bin
0d3f720a21ea2d85e9f3caf6a74cab1a2ef4356c9a3792dc13153d868e2e63d6
rtf-objdata-decoded RTF \objdata at offset 0x113C 2268 bytes