Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c8deccf878f3a069…

MALICIOUS

RTF / .DOC

29.5 KB First seen: 2023-04-11
MD5: 24373ca3977c5b7a6a6946d41e92e663 SHA-1: 1eca9207182580d3b9cde0848b139b4a63e0b966 SHA-256: c8deccf878f3a069c62aa1c0ee01811b4c06ace8671d98e55c51c6727ebcee66
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains an embedded OLE object with a split Equation Editor ProgID and an objupdate directive, strongly indicating an attempt to exploit a known vulnerability. The document body includes a lure instructing the user to 'Enable editing', which is a common tactic to bypass macro security and trigger the exploit. The primary IOC is the file's SHA256 hash.

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_off0000480c.bin
76f389d0d7a16d9b4e091646eef089a75bca546f9987272d67b0ca77a98f6a6a
rtf-objdata-decoded RTF \objdata at offset 0x480C 1637 bytes