Malicious RTF — malware analysis report

Static analysis result for SHA-256 d9bbb83ff0e4e268…

MALICIOUS

RTF

510.8 KB First seen: 2018-09-04
MD5: cf35a02a6e70964dd87bc0c1adc768a1 SHA-1: f3a52e4ca4295de8f399759c4f1faef2da9b3fc4 SHA-256: d9bbb83ff0e4e268d91aa1d7eb21db9daa28d2fffc4abde74ffdc4940dad01ae
180 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. Heuristics indicate a high likelihood of exploitation for CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. This vulnerability is commonly used to execute arbitrary code, suggesting the RTF document is a delivery mechanism for a malicious payload.

Heuristics 5

  • 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_off0000138f.bin rtf-objdata-decoded RTF \objdata at offset 0x138F 4154 bytes
SHA-256: 0110a25f594efd02b8c69800e3703fc9f7c8be3a85af44137b0d091b5aa078c6