Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 40990627a2c50a6d…

MALICIOUS

RTF / .DOC

38.2 KB First seen: 2023-05-19
MD5: e1e674000c143160f0187188913dac27 SHA-1: c9ca520dae910e2440eadcbd389af8e50c3b8f44 SHA-256: 40990627a2c50a6dcaa85b143ac2da99a573be1a9f0172363ce73531c380b282
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, indicating an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882). The \objupdate directive forces OLE activation, and the document body includes a lure instructing the user to 'Enable editing', which is a common technique to bypass macro security settings and trigger the exploit. The primary goal appears to be initial compromise via a known Office vulnerability.

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_off00005c20.bin
ba487e8d807a3a3affb0522e3df98d707127dc0ec8c3603062ac158df261b793
rtf-objdata-decoded RTF \objdata at offset 0x5C20 1423 bytes