Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8267f629be2a8d0…

MALICIOUS

PDF

82.0 KB Created: 2021-10-18 17:09:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 00596fc83e09e9347eddb7ef34027892 SHA-1: 31ab152a6e23fca1fe937f9c9e416b48c6820846 SHA-256: f8267f629be2a8d0250c4cc127ba3bd85df43f3c4100f6697ed37486a2872165
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier with high confidence. It contains numerous embedded URLs pointing to a link farm, with one specific URL identified as potentially disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://oguraclutch.cn/uploadfile/files/39234138630.pdf In PDF document text
    • http://odra.cycling-recycling.eu/imgturysta/files/sedimej.pdfIn PDF document text
    • https://gilbertems.com/videos/file/63498794934.pdfIn PDF document text
    • https://takitech.hu/userfiles/file/78047489699.pdfIn PDF document text
    • http://kco.su/userfiles/file/84623905433.pdfIn PDF document text
    • https://bold-iot.com/uploads/files/202109211034411274.pdfIn PDF document text
    • http://kamakuralosgatos.com/uploads/files/54183216127.pdfIn PDF document text
    • http://abwlargo.com/uploads/files/damekizifunet.pdfIn PDF document text
    • http://www.marcado.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1616d1fb4c642d---lidulanolowiz.pdfIn PDF document text
    • https://olterus.info/contents/files/diwonuzisodifubekakix.pdfIn PDF document text
    • http://ingegneriarossi.it/userfiles/files/53120400754.pdfIn PDF document text
    • http://baharemadinah.com/wp-content/plugins/formcraft/file-upload/server/content/files/16149d7822bf01---82441611663.pdfIn PDF document text
    • http://epmresearch.org/userfiles/files/45891691451.pdfIn PDF document text
    • https://ceramicasvillaflor.cl/UserFiles/File/9570284922.pdfIn PDF document text
    • https://linhan.xelinhan.vn/userfiles/file/joxokeki.pdfIn PDF document text
    • http://versobrokers.eu/userfiles/files/17966620414.pdfIn PDF document text
    • http://mitroc.com/userfiles/file/27038734429.pdfIn PDF document text
    • https://termofriz.rs/files/dotefigalirasikegiwaje.pdfIn PDF document text
    • http://tahi.hu/ckfinder/userfiles/files/jagarudabujitojemalebofok.pdfIn PDF document text
    • http://candemdientu.com/Images_upload/files/buzedazuwerurop.pdfIn PDF document text
    • https://edenestates.com/ckfinder/userfiles/files/zosipurozajolisabuwe.pdfIn PDF document text
    • http://hitecds.com/userfiles/file/nutikubotixutis.pdfIn PDF document text
    • http://radiosalsa.fr/php/rs/filesupload/file/1855641780.pdfIn PDF document text
    • http://dade666.com/userfiles/202109file/2021090704323170554.pdfIn PDF document text
    • http://iscelenie.info/files/file/80499136200.pdfIn PDF document text
    • https://congtydaihai.com/upload/files/lotadenadilikawolaris.pdfIn PDF document text
    • http://feedproxy.google.com/~r/MbOu/~3/896FEnmJZlk/uplcv?utm_term=online+pdf+protectorPDF 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_off0000dd44.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD44 18088 bytes
SHA-256: 6e3f8363d1458f421199b260b75193efddbc224c19604d4e601dadb1efd1b659
font_01_sfnt_off00010afb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AFB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012312.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12312 10308 bytes
SHA-256: 6f1409f0f2ccba38839aa1cc1c6aa38e8a10bbce32fdd3a5475bedd88db79407