Malicious RTF — malware analysis report

Static analysis result for SHA-256 cfab994da38e13e7…

MALICIOUS

RTF

12.2 KB First seen: 2022-07-27
MD5: c625a2239ee08ca0678dbb1615faae3a SHA-1: 914fa9b2811cd290b9a7c303010bb2be7e1e7996 SHA-256: cfab994da38e13e7f60522a85db03e1b25b04dbc3d474d27588dadcb868ec3d3
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File Execution: Malicious Attachment T1059.005 Command and Scripting Interpreter: Visual Basic

The RTF document contains an embedded OLE object with an obfuscated Equation Editor ProgID, indicative of CVE-2017-11882 exploitation. The presence of RTF_OBJUPDATE and SE_ENABLE_LURE heuristics suggests the document is designed to trick the user into enabling editing, which then triggers the OLE object's activation. This activation likely leads to the execution of a malicious payload, commonly a downloader.

Heuristics 6

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • \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 2 \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_off00001c80.bin
fd33d20c2176b4056d84a12a53add8a4af5d2c046a42648d050d58658cd64cc8		 rtf-objdata-decoded RTF \objdata at offset 0x1C80 1568 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.