RTF malware analysis — malicious · 9501619a86092f5f

MALICIOUS

RTF

131.8 KB First seen: 2018-05-18

MD5: 30082e9e7c6344211a930a4c1bcc4ee9 SHA-1: a3800f26feeade03322fe98a2d90a596644042da SHA-256: 9501619a86092f5fb4cd0145b2ca3e623c44abc169e0ca58608facdfa1cd2ddf

320 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The presence of the Ole10Native stream and the specific CLSID strongly indicate this exploit. The document also contains a lure to enable editing, which is a common tactic for malicious documents to bypass security measures and execute the embedded exploit.

Heuristics 8

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.
ClamAV: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
\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
Macro/content-enable lure medium SE_ENABLE_LURE

Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000086.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x86	45379 bytes
SHA-256: `da44eedc0edd2409432c887ddca443fa84c8a903639d9a6aa769e5c8500eb633`

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