Malicious PDF — malware analysis report

Static analysis result for SHA-256 850b79c6ad346427…

MALICIOUS

PDF

77.1 KB Created: 2021-09-16 10:26:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 90d08fa12af194479720720c1f19476f SHA-1: 6a29e9f83ec493ae64bdfd82ee61b05bf42febff SHA-256: 850b79c6ad34642707449454c5cd989240bd8064f2ad16b81c8f512752ca09a5
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, suggesting a phishing or malware distribution scheme. The document body is heavily obfuscated and does not provide clear textual lures, but the overall structure and heuristic firings indicate a malicious intent to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://emrc.ie/upload/imagecontent/file/zugewogerulema.pdf In PDF document text
    • http://shanghaicruiseparty.com/uploads/file/pupevelumetalazoso.pdfIn PDF document text
    • http://studiorinaldibedin.eu/userfiles/files/65328602920.pdfIn PDF document text
    • http://ieltsadd.ir/cache/fck_files/file/visepezivilulavakilanowuf.pdfIn PDF document text
    • https://www.pietri-automobiles.com/wp-content/plugins/super-forms/uploads/php/files/9ioihmgg9vm4k8rulkf60v0p8l/9916304466.pdfIn PDF document text
    • https://gulamanis.com/contents/files/94230616686.pdfIn PDF document text
    • http://xn--ob0bjxt9h99icicrvkksa421cwwp7hiv4d6a.net/ckfinder/userfiles/files/bowinoto.pdfIn PDF document text
    • http://le-lemniscus-incandescent.fr/ckeditor/upload/files/jilesujo.pdfIn PDF document text
    • http://w-mill.jp/images/file/35854770088.pdfIn PDF document text
    • http://www.physedu.in/newsite/userfiles/files/sipat.pdfIn PDF document text
    • https://implant-drill.com/userfiles/file/36291906309.pdfIn PDF document text
    • https://rinducm1.com/contents/files/7320985225.pdfIn PDF document text
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613cfc4778359---55549967398.pdfIn PDF document text
    • http://businessvaluationapp.com/fck_files/file/bonase.pdfIn PDF document text
    • https://ochronaskory.pl/pliki_user/File/27566788724.pdfIn PDF document text
    • http://onlinepravenconsultant.com/uploads/wysiwyg/files/38482287146.pdfIn PDF document text
    • https://www.abrasco.org.br/ckfinder/userfiles/files/61132168659.pdfIn PDF document text
    • https://sharzh-ufa.ru/wp-content/plugins/super-forms/uploads/php/files/0a96852731f2da56658561c0aa77644b/titepusozef.pdfIn PDF document text
    • http://www.dgtrans.co.th/login/ckfinder/userfiles/files/katedosejowo.pdfIn PDF document text
    • https://hotelristorantenovecento.it/wp-content/plugins/super-forms/uploads/php/files/f0e024c0df592e8d5fcae69f686cf29a/towexeveron.pdfIn PDF document text
    • https://homeuu.biz/upload/ckeditor/pages/files/sasimaki.pdfIn PDF document text
    • http://asavn.vn/uploads/userfiles/files/fuvurufixafetipabutomota.pdfIn PDF document text
    • https://kaptenhoki.org/contents/files/96790109735.pdfIn PDF document text
    • https://elitstroycraft.ru/source/file/xowemijipit.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=three+letter+words+that+end+with+oPDF 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_off0000c861.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC861 10392 bytes
SHA-256: a204f6c4f245c8da958d87370147447c09ea1d8dac54189d55d94150dad7e20e
font_01_sfnt_off0000dfe3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFE3 18180 bytes
SHA-256: 4ca8bf42678ad2246d40f6f31836bc4ab3b3a08ab2b30f06e28cfd0f569e89d3
font_02_sfnt_off00010f00.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F00 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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