Malicious RTF — malware analysis report

Static analysis result for SHA-256 bcf86a0d4685aaaa…

MALICIOUS

RTF

841.6 KB Created: 2018-03-12 22:09:00 First seen: 2018-06-25
MD5: 284acfeb8f427c3777a09478c7903c0d SHA-1: 8406e8848273c83c3355187dd413410591916c21 SHA-256: bcf86a0d4685aaaa6a1266426081b047694ccff9cdb1684e3272dedd469ed70c
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: Xls.Downloader.Generic-6750544-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Generic-6750544-0
  • \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 10 \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 10

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00002c50.bin rtf-objdata-decoded RTF \objdata at offset 0x2C50 28731 bytes
SHA-256: 99b74f785d2bdf34a327ca2e297b5a0b650df6e7e9c72377997e4835a895fe75
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely
objdata_01_off00016cb5.bin rtf-objdata-decoded RTF \objdata at offset 0x16CB5 28731 bytes
SHA-256: 6dd65ae33d451212d166003d81deff7f06f481ec9284cbda26347b29a3dc4304
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely
objdata_02_off0002ad1a.bin rtf-objdata-decoded RTF \objdata at offset 0x2AD1A 28731 bytes
SHA-256: 2766a9a5b9bdcd77790acf8782583869eb9f20015c3d98563f5fe53c4396aedd
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely
objdata_03_off0003ed7f.bin rtf-objdata-decoded RTF \objdata at offset 0x3ED7F 28731 bytes
SHA-256: a5e6fbdd7355f81fbc1a763b3261d447f9d5394dc400390ddb68ba37c446bf89
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely
objdata_04_off00052de4.bin rtf-objdata-decoded RTF \objdata at offset 0x52DE4 28731 bytes
SHA-256: 597c8e26ddec113499273e981f3030365fd7a803f88730e3154186cf04be65c6
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely
objdata_05_off00066e49.bin rtf-objdata-decoded RTF \objdata at offset 0x66E49 28731 bytes
SHA-256: c71c9b92b4daac29bc2d647afaeb321cb89dacfa016f97ee17d65df028e0bac1
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely
objdata_06_off0007aeae.bin rtf-objdata-decoded RTF \objdata at offset 0x7AEAE 28731 bytes
SHA-256: 8d2ce4c84ee4f26202fe157665149bc643d050bd239d11e78635bcbff150e448
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely
objdata_07_off0008ef13.bin rtf-objdata-decoded RTF \objdata at offset 0x8EF13 28731 bytes
SHA-256: 638e0a4af2fd30ebd2877c8eebaf2ef3c693add75ec84f3f315234e3e99cedc2
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely
objdata_08_off000a2f78.bin rtf-objdata-decoded RTF \objdata at offset 0xA2F78 28731 bytes
SHA-256: 5a4df2ef1d6a121fdb89597f0fb141a012e62db794140847c5632db059ba2bde
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely
objdata_09_off000b6fdd.bin rtf-objdata-decoded RTF \objdata at offset 0xB6FDD 28731 bytes
SHA-256: 929efba185c57add9d7ea8c8a7f8fb737f77e284022e8c01055dbaabb974fef8
Detection
ClamAV: Xls.Downloader.Generic-6750544-0
Obfuscation or payload: unlikely

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