Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 99ecfda54daa294d…

MALICIOUS

RTF / .DOC

43.9 KB First seen: 2023-05-26
MD5: 64a8921c395f7b802394787e4d834d00 SHA-1: 2b5afddb44fb6b1f24a9ec4abd56385f94546cd7 SHA-256: 99ecfda54daa294d75b8df1d697e916bb8b3a0f415efc6d75db141d87b7d15b7
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1059.005 Visual Basic

The sample is an RTF document that contains an OLE object and an Equation Editor ProgID, indicating a likely exploit attempt. The document body presents a lure, instructing the user to 'Enable editing' to view the content, which is a common technique to bypass macro security settings and initiate malicious activity. The presence of RTF_OBJUPDATE further suggests that the embedded OLE object is intended to be activated automatically.

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_off0000581d.bin
2c2a942e1d9716110c92cd82da8cc042b5c5004de5306b7f1ea0f3698c6b9ff9
rtf-objdata-decoded RTF \objdata at offset 0x581D 2049 bytes