Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 a3558dc9bbc68b36…

MALICIOUS

RTF / .DOC

12.5 KB First seen: 2022-10-05
MD5: 309cc3f93d34c55cb92d56a5a7b0f8f0 SHA-1: 38c025f28c962ada9fc4975be35f9f58ca6860a2 SHA-256: a3558dc9bbc68b365d3a510fb97d1377cb4c6929b9ca2571f948870cf616aefc
200 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 T1059.005 Command and Scripting Interpreter: Visual Basic

The file is an RTF document that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. The document body contains a lure instructing the user to enable editing, which is a common tactic to bypass security measures and execute embedded malicious content. The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED heuristics strongly indicates this exploit.

Heuristics 6

  • 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.
  • 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_off00000aa1.bin
00fdb52f42e430934b03ce6de3300ef3d768b559cdd026d0591eb582c65773e5		 rtf-objdata-decoded RTF \objdata at offset 0xAA1 1826 bytes

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