Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 3491ffa7b3d64ed2…

MALICIOUS

RTF / .DOC

17.5 KB First seen: 2022-08-15
MD5: 44d1b4fbec745292186b3308a6b2d6a6 SHA-1: e8d7bda6fb8709b3365ffde49c6e23c22f3814a8 SHA-256: 3491ffa7b3d64ed2cc7ab30130fd1e94e4442e5017cd63f5af3958a3e580b732
260 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 Malicious Link

The sample is an RTF document containing an OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). This technique is commonly used to deliver a second-stage payload. The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_EQUATION_OLE10NATIVE heuristics strongly indicates exploitation of this known vulnerability.

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
  • 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000ffd.bin
df208a68273cada6058fd1467f25b18f07e3837ff3a1cde70f242391fe8fc51a		 rtf-objdata-decoded RTF \objdata at offset 0xFFD 3758 bytes

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