Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 d4cdda5b242368d9…

MALICIOUS

RTF / .DOC

11.7 KB First seen: 2022-03-18
MD5: 95137cd60e199ae22b157f464dc29d7b SHA-1: 9cb68e0d816faabcc28df3f067aa323716e245f2 SHA-256: d4cdda5b242368d9f28293640d660b52185bd5a0f17e41866d7d5fedffede2b8
121 Risk Score

Malware Insights

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

The sample is an RTF document that contains embedded OLE object data, specifically targeting the Equation Editor. The RTF_OBJUPDATE heuristic indicates that the embedded object is designed to be activated automatically. This strongly suggests exploitation of a known vulnerability in the Equation Editor (CVE-2017-11882) to achieve arbitrary code execution. The primary goal is likely to download and execute 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001e31.bin
d63c6dc24d2a5a14db732258ee8e9fdc80150bb2dce48d65b2d6afaffa19076f
rtf-objdata-decoded RTF \objdata at offset 0x1E31 1929 bytes