Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 810109d0cd9c7376…

MALICIOUS

RTF / .DOC

10.2 KB First seen: 2022-04-11
MD5: ded03151851f989fcc1a9576f9dfdf95 SHA-1: 19af3e29f591b634716a791f83a7ca01669f9889 SHA-256: 810109d0cd9c7376dfe60ae221905a20d9e14475228554ff22a4656d038207e8
160 Risk Score

Malware Insights

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

The sample is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882) to achieve code execution. The presence of \objupdate and \objdata heuristics indicates that an embedded OLE object is being activated and its data is being processed. This typically leads to the download and execution of a second-stage payload, although no specific URLs or scripts were extracted in this instance. The attack pattern is consistent with exploiting a known Microsoft Office vulnerability for initial access.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off00001947.bin
29603f1c86bd4eb90e93b51c5d8d4d36d53cf43e5da1f3a96920bc2186ae7ed9
rtf-objdata-decoded RTF \objdata at offset 0x1947 1877 bytes