Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 917d8fa4a7292f7f…

MALICIOUS

RTF / .DOC

20.6 KB
MD5: c06dc096b855a7050bfd2b9ade98decc SHA-1: 5f503c9889fba0017f06665614781b2500534e89 SHA-256: 917d8fa4a7292f7f24c1b59f20a8ff83622642bd1950f208baa01b2c01d4cf32
120 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 objects and triggers an ".objupdate" call, indicating an attempt to activate embedded content. The critical heuristic "RTF_EQUATION_EDITOR" strongly suggests exploitation of the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for arbitrary code execution, which is likely used here to download and execute a second-stage payload. No document body text or scripts were extracted, limiting further analysis of the payload's specific actions.

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_off000014df.bin
1c98371c8a101412cac8f97f51d3ddd674ca5aab4ac7547bf82ada95964a845b
rtf-objdata-decoded RTF \objdata at offset 0x14DF 1599 bytes