Malicious RTF — malware analysis report

Static analysis result for SHA-256 597c0c6f397eefb0…

MALICIOUS

RTF

940.3 KB Created: 2018-03-14 17:34:00 First seen: 2019-01-31
MD5: 88d667cc01c4d8ee32e9de116f3bfdeb SHA-1: 5ca26b6eae6bdf038c4ec61b174a3825bcde95fd SHA-256: 597c0c6f397eefb06155abdf5aa9a7476c977c44ef8bd9575b01359e96273486
320 Risk Score

Malware Insights

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

The RTF file contains embedded OLE objects, specifically exploiting the Equation Editor vulnerability (CVE-2017-11882). This vulnerability is known to be used for client-side execution of arbitrary code, typically to download and run a secondary payload. The ClamAV detection name 'Rtf.Dropper.Agent-6988897-0' further supports its role as a dropper.

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 OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
  • ClamAV: Rtf.Dropper.Agent-6988897-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-6988897-0
  • \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.
  • Package object class high RTF_OBJCLASS_PACKAGE
    OLE Package object — can wrap arbitrary files
  • OLE object data medium RTF_OBJDATA
    RTF contains 3 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000ba3e.bin rtf-objdata-decoded RTF \objdata at offset 0xBA3E 447728 bytes
SHA-256: 14148e052eb0b376e498c5a2978ef1c944ae583122e86c7d66d5974d47d7bde6
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.
objdata_01_off000e6454.bin rtf-objdata-decoded RTF \objdata at offset 0xE6454 9781 bytes
SHA-256: 20f8b7ac964442c1266cca393e812ee31197416f72cdd9335aa9f521a415db00
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis found candidate code region(s). Indicators: SC_GETPC_CALL, SC_STR_VIRTUALPROTECT Static shellcode analysis recovered API/import strings: VirtualAlloc, VirtualAllocEx, VirtualProtect, VirtualProtectEx, WriteProcessMemory, ReadProcessMemory
objdata_02_off000e6466.bin rtf-objdata-decoded RTF \objdata at offset 0xE6466 35 bytes
SHA-256: 1188b98b21f50564ab8b476f25b6deab999a2f58a56c4dd0daa0f5883cfa941d