Malicious RTF — malware analysis report

Static analysis result for SHA-256 27a76df4fef94ac1…

MALICIOUS

RTF

422.9 KB Created: 2019-03-12 22:25:00 First seen: 2020-09-04
MD5: 9c70de8b2e6de89be3c1376fbf7fe090 SHA-1: b2a5d402efe0b25adbc81591fa7da4dbd5974954 SHA-256: 27a76df4fef94ac189118565478584751781b2a70e616e21e57e4ee478bccc96
262 Risk Score

Malware Insights

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

The RTF file contains multiple embedded OLE objects and triggers an ".objupdate" command, which is indicative of exploiting vulnerabilities like CVE-2017-8759 for client execution. ClamAV detections further confirm its malicious nature, flagging it as Doc.Macro.Obfuscation. The primary attack vector is likely spearphishing attachment, with the embedded OLE object serving as the mechanism to download and execute a secondary payload.

Heuristics 6

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • ClamAV: Doc.Dropper.Agent-6948043-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6948043-0
  • \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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 7 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2003/wordml In RTF body

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00002d00.bin rtf-objdata-decoded RTF \objdata at offset 0x2D00 16955 bytes
SHA-256: 2f932e28be552b90ae6650c6ad98942a640621197db4182bf6575d74c96e9c38
Detection
ClamAV: Doc.Dropper.Agent-6948043-0
Obfuscation or payload: unlikely
objdata_01_off0001074b.bin rtf-objdata-decoded RTF \objdata at offset 0x1074B 16955 bytes
SHA-256: 4bafe78fae219d4a9855b12394604029d96da41dc2c014cc7fbaa8384a311723
Detection
ClamAV: Doc.Dropper.Agent-6948043-0
Obfuscation or payload: unlikely
objdata_02_off0001e196.bin rtf-objdata-decoded RTF \objdata at offset 0x1E196 16955 bytes
SHA-256: 19c888256834f38fc1f6c685ea31c71938716fff760e5d81218058f55162684f
Detection
ClamAV: Doc.Dropper.Agent-6948043-0
Obfuscation or payload: unlikely
objdata_03_off0002bbe1.bin rtf-objdata-decoded RTF \objdata at offset 0x2BBE1 16955 bytes
SHA-256: d217a143501839992fd4588a3d2d4d4368dff8ce8ef5caaf5bd0b8536aeaa4ab
Detection
ClamAV: Doc.Dropper.Agent-6948043-0
Obfuscation or payload: unlikely
objdata_04_off0003962c.bin rtf-objdata-decoded RTF \objdata at offset 0x3962C 16955 bytes
SHA-256: 4fabe550852b50ee702ec0cf6851f4a995ab85d0890d7e4fc3c675c20a2ba422
Detection
ClamAV: Doc.Dropper.Agent-6948043-0
Obfuscation or payload: unlikely
objdata_05_off00047077.bin rtf-objdata-decoded RTF \objdata at offset 0x47077 16955 bytes
SHA-256: 3c720352c0afded4b68c232074ee6662228b8d5f3c8b66e9d0df574cf53e6974
Detection
ClamAV: Doc.Dropper.Agent-6948043-0
Obfuscation or payload: unlikely
objdata_06_off00054ac2.bin rtf-objdata-decoded RTF \objdata at offset 0x54AC2 16955 bytes
SHA-256: d6aeab81a9f869da5fde554ca677582daf9d2734a349fbfcc1c4b730edf78722
Detection
ClamAV: Doc.Dropper.Agent-6948043-0
Obfuscation or payload: unlikely