Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 2a096c6c0c741890…

MALICIOUS

RTF / .DOC

22.9 KB First seen: 2022-12-13
MD5: b925228212a013a56c8cbf663613da44 SHA-1: 205d1193428fadd24d97274c622e6426ea05c1b9 SHA-256: 2a096c6c0c7418909916023372da7fe806e75aa1c7c3f32ccfde9b7e8741ddb1
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic

The file is an RTF document containing an embedded OLE object that exploits CVE-2017-11882 via the Equation Editor. The document body includes a lure to 'Enable editing' to bypass security measures. The presence of the Equation Editor object and the lure strongly indicate an attempt to execute arbitrary code.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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
  • 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_off00004ae7.bin
7fb733622d885b2c726391c1e09e8fe779d827c2a41cde278a74fbef696e5527
rtf-objdata-decoded RTF \objdata at offset 0x4AE7 1674 bytes