Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 22d0b4c2c6256e73…

MALICIOUS

RTF / .DOC

30.5 KB First seen: 2023-03-31
MD5: 61d8bbf815b071d980aa91c141bfd896 SHA-1: f65ce51936aa0f68d15b7a43e1eece852d38245e SHA-256: 22d0b4c2c6256e73bcb60045f47f342465f8d9535c848bf6201730b26cf10f50
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1204.002 Malicious File

The sample is an RTF document that leverages OLE object embedding and an ".objupdate" directive to trigger the execution of embedded content, specifically targeting the Equation Editor vulnerability. The document body contains a lure instructing the user to 'Enable editing' to view the content, which is a common tactic to bypass macro security settings and facilitate the execution of malicious payloads.

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_off000046c2.bin
cbfd4280c2e26030c17bf95752acf7379981bc713eae0dc8c8c1a62475294c2e
rtf-objdata-decoded RTF \objdata at offset 0x46C2 1632 bytes