Malicious RTF — malware analysis report

Static analysis result for SHA-256 d4f9b72046ec53ce…

MALICIOUS

RTF

11.2 KB First seen: 2019-12-10
MD5: b00a9021fc74333ecad132fc50e664bf SHA-1: 74d65f1144881f212e3b25855d23cdd6be3f36ea SHA-256: d4f9b72046ec53ce1f1059e981493327d273eb1aa6dae375a873906767c075f3
240 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object exploiting CVE-2017-11882 via Microsoft Equation Editor. This vulnerability allows for arbitrary code execution, which is typically used to download and execute a second-stage payload. The presence of the Equation Editor CLSID and Ole10Native stream strongly indicates 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_off00000a30.bin rtf-objdata-decoded RTF \objdata at offset 0xA30 4178 bytes
SHA-256: 9cada3d505f129ae9aa8a1d60690a0582996274e74cea8a8e04248265b6e3483

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