Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e85c696a1e55cc32…

MALICIOUS

RTF / .DOC

27.4 KB First seen: 2023-04-11
MD5: 2fc2480e320185ef983263deac897951 SHA-1: 4d832dbb346c3f4f0a09c65434a6c2cb14a3f365 SHA-256: e85c696a1e55cc322a08ddeba57b415f688f29b1542378feaabe985dde382f83
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic

The RTF document contains an embedded OLE object, specifically targeting the Equation Editor, and uses an \objupdate directive to force its activation. The document body includes a lure instructing the user to 'Enable editing', a common tactic to bypass macro security. This combination strongly suggests an exploit attempt, likely leveraging a known vulnerability in the Equation Editor to execute a malicious payload.

Heuristics 5

  • 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off0000442d.bin
beb9b008227a6df9a56bbc474681d884aba3f90807b14c1b070fccb03e591ad5
rtf-objdata-decoded RTF \objdata at offset 0x442D 1499 bytes