Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 753af90c3cddb8e6…

MALICIOUS

RTF / .DOC

91.8 KB First seen: 2023-09-26
MD5: 6d6cf0f509f2ca39bcf65f5569af77c0 SHA-1: b64c7bbe50cbc2a7fab7cf25769f464a5fe4d3ef SHA-256: 753af90c3cddb8e64a8b462689f63e8fc784ed052d6b479c6a64b63f567a8114
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1566 Phishing T1566.001 Phishing: Spearphishing Attachment T1059 Command and Scripting Interpreter

The sample is an RTF document containing an embedded OLE object, specifically leveraging the Equation Editor vulnerability. The document body provides a lure about financial statements, instructing the user to 'Enable editing' and likely macros. This combination strongly suggests an attempt to exploit 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_off00003bdd.bin
afd7217237c2d96dd9dcdeb41039c17d14034aeafa4e91e15f463959c2dba316
rtf-objdata-decoded RTF \objdata at offset 0x3BDD 1656 bytes