Malicious RTF — malware analysis report

Static analysis result for SHA-256 b508484b567fce9d…

MALICIOUS

RTF

10.8 KB First seen: 2019-10-30
MD5: d58127dbf2b9cca4db3017ae7a3523fd SHA-1: 8241b5b2135d42c73f526fcb368b5953fc8b0281 SHA-256: b508484b567fce9d19df328ad131d8bca24a6a99389cf692e5041d68ef025c4d
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains an embedded OLE object that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This exploit allows for arbitrary code execution, which is typically used to download and run a second-stage malicious payload. The presence of the Equation Editor CLSID and the Ole10Native stream strongly indicate this exploit.

Heuristics 6

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • 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.
  • \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_off00000adb.bin rtf-objdata-decoded RTF \objdata at offset 0xADB 4146 bytes
SHA-256: 88085e89c5aeff06a8efe1a82d94377fb7060483026b6bba7caac1e3186b7637

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