Malicious RTF — malware analysis report

Static analysis result for SHA-256 c1b456fa640428fb…

MALICIOUS

RTF

7.4 KB First seen: 2019-06-27
MD5: 650bb11717dfe136a4e93c76d6ff38f9 SHA-1: b6d2c34b718170206c8227f109e2e2a47fb6e175 SHA-256: c1b456fa640428fbd3db723a627fcbfaa04b0fce5bb1012ac3017c34b898f798
140 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 Equation Editor vulnerability (CVE-2017-11882). This technique is commonly used to deliver a second-stage payload, likely shellcode as indicated by the 'Shellcode candidate region' heuristic. The file's structure and heuristic firings strongly suggest exploitation for client execution, likely delivered via spearphishing.

Heuristics 4

  • 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
  • \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
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000033.bin rtf-objdata-decoded RTF \objdata at offset 0x33 3636 bytes
SHA-256: 517c90f1325c104b274c415291f9f3413de8ebebfb421b6c7ff9978095fdcd1b
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis found candidate code region(s). Indicators: SC_GETPC_CALL