Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 b0258ce32d2aca03…

MALICIOUS

RTF / .DOC

81.0 KB First seen: 2023-10-16
MD5: 34cb615513b46dec1d930797c05c9016 SHA-1: 861d3a13f685add044c070e08aeb093b50a91e01 SHA-256: b0258ce32d2aca03e0d56c4eae2c30692d5828bce0728ca4d82b5d99ff066abc
160 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object, specifically targeting the Equation Editor vulnerability, and includes an ".objupdate" directive to force its activation. The document body presents a lure about financial audits, instructing the user to 'click Enable editing', which is a common tactic to bypass macro security settings and execute the embedded exploit.

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_off00003c32.bin
b0067c10890fab3e5070a096ecd7f6e617a126c41b331e30c9c67502baadfae5
rtf-objdata-decoded RTF \objdata at offset 0x3C32 1590 bytes