Malicious PDF — malware analysis report

Static analysis result for SHA-256 bf6bb866bcaa0192…

MALICIOUS

PDF

96.7 KB Created: 2021-10-07 10:07:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: fdb7d7c4908e533a18ab4f5edb3ce3ad SHA-1: 611d07f88235532f603424b065a8dd404fb59b00 SHA-256: bf6bb866bcaa01928395cc56ae801406575501cd1e0ead57b2eb05c4f17f1e1b
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, exhibiting characteristics of a malformed exploit stream. It contains numerous embedded URLs that form a link farm, suggesting an attempt to redirect users to potentially malicious sites. The PDF structure and embedded content indicate it's likely part of a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://metrominicabs.com/survey/userfiles/files/63610729409.pdf In PDF document text
    • http://edbiji.com/uploads/files/20210925151634_466418.pdfIn PDF document text
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16156bd632fe40---binifusikaxod.pdfIn PDF document text
    • http://bubb.cn/up_file/file/21688980186.pdfIn PDF document text
    • http://www.motocams.cz/ckfinder/userfiles/files/lijegoxufuzuz.pdfIn PDF document text
    • https://verner.lt/images/files/ruzad.pdfIn PDF document text
    • http://colorsoftexas.com/ckfinder/userfiles/uploads/51621510503.pdfIn PDF document text
    • https://quangcaowebsitecomvn.xemlaco.com/uploads/files/paboxorav.pdfIn PDF document text
    • http://antracit.topmebli.com/content/xuploadimages/file/52847623710.pdfIn PDF document text
    • http://broadviewlibrary.org/uploaded_bvlib/file/rigoloja.pdfIn PDF document text
    • http://bjyhyy.cn/filespath/files/20210912031720.pdfIn PDF document text
    • https://philly.drinkpoint.com/uploads/files/fanade.pdfIn PDF document text
    • http://imbirimbir.ru/files/xarowerowupinulomidiwani.pdfIn PDF document text
    • http://studioriboldi.eu/userfiles/files/kivin.pdfIn PDF document text
    • https://apc-algercentre.dz/ckfinder/userfiles/files/59141822343.pdfIn PDF document text
    • http://nairmobilya.com/userfiles/file/73026435469.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=infinite+limits+and+vertical+asymptotesPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000107cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107CF 23520 bytes
SHA-256: f64f913f3e6872f486a95ad3774db0635246ba527c040d86bd0d767206564139
font_01_sfnt_off00014461.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14461 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00015c78.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15C78 10912 bytes
SHA-256: 5a8b053182952446eb905349da42ff9176b670d1164df53aeab2fbdc2abd1dcd

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