Malicious RTF — malware analysis report

Static analysis result for SHA-256 8cf00aee74d8472f…

MALICIOUS

RTF

28.9 KB First seen: 2023-05-15
MD5: 2b52e3645953f9c89870ecf02cf7c0c5 SHA-1: 54fbb5afec0ef993f42cdd89692087312e65ffb9 SHA-256: 8cf00aee74d8472f200018714e866884689c7256f70d5c229232eb16843f6897
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an RTF document containing an embedded OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). This vulnerability is known to be used for arbitrary code execution, typically to download and run a second-stage payload. The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_EQUATION_OLE10NATIVE heuristics strongly indicates this exploit.

Heuristics 6

  • Equation Editor Ole10Native payload — CVE-2017-11882 likely critical CVE likely CVE_2017_11882_EQUATION_OLE10NATIVE
    RTF decodes to an activated Microsoft Equation 3.0 OLE storage whose payload is a high-entropy Ole10Native stream rather than normal Equation Native/MTEF data. This is a weaponized Equation Editor RCE delivery shape consistent with CVE-2017-11882/CVE-2018-0802.
  • Ole10Native stream in RTF OLE object high CVE related RTF_OLE10NATIVE_STREAM
    RTF contains an embedded OLE object with an Ole10Native stream. This is a strong payload-container signal and is related to Word/OLE exploit delivery, but it is not specific enough on its own to assign a CVE.
  • Equation Editor CLSID critical RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • \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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00002072.bin
8b7093ad312a3e448be55438713f992416668a432028bc8c6e516e4bdec4af3a		 rtf-objdata-decoded RTF \objdata at offset 0x2072 4191 bytes

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