Malicious PDF — malware analysis report

Static analysis result for SHA-256 13662185327bcea8…

MALICIOUS

PDF

85.1 KB Created: 2021-09-08 19:50:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 4f2617e0a60d2a455cd29a838be93967 SHA-1: fefd18ade9d1e8547edc2db7a16158ebfde1c2ce SHA-256: 13662185327bcea8949c96d805cd65ff4ac715591920ab6862d8da51dc829d87
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to potentially compromised or disposable hosting sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 https://mokhalasati.com/userfiles/files/pazuxawiwonarab.pdf In PDF document text
    • http://satunatc.ac.th/ckfinder/userfiles/files/78726962951.pdfIn PDF document text
    • http://jogamiskolc.hu/ckfinder/userfiles/files/95160258881.pdfIn PDF document text
    • http://artmetinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130e78540c48---33216978973.pdfIn PDF document text
    • http://andrenickels.de/ckfinder/userfiles/files/16510624685.pdfIn PDF document text
    • https://cplastik.com/data/cms/file/wutobusad.pdfIn PDF document text
    • http://edilcfcostruzioni.com/userfiles/files/71615622857.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16135e895b0c3c---fifojasavezi.pdfIn PDF document text
    • http://sqc.jp/user_data/editor/ckfinder/core/connector/php/upload/files/nujok.pdfIn PDF document text
    • http://www.eau-msu.ru/ckfinder/userfiles/files/73598928567.pdfIn PDF document text
    • http://slesnick.net/userfiles/files/tewifisasatat.pdfIn PDF document text
    • http://dalieuht.com/app/webroot/uploads/files/43691588221.pdfIn PDF document text
    • http://bigcool.net/webroot/img/files/27038610960.pdfIn PDF document text
    • https://hkparkkonutlari.com/image/files/wibulafofexujojat.pdfIn PDF document text
    • http://dintainoodle.com/uploads/files/nenasobesolatawiwibes.pdfIn PDF document text
    • http://kaies.net/upfiles/210908074205056619m3xirx.pdfIn PDF document text
    • https://cs-nippon-cp.com/mailmagazine/upload/files/bebajotowerudipoli.pdfIn PDF document text
    • https://www.lesson-online.org/wp-content/plugins/super-forms/uploads/php/files/o0bousu7kijr2ii71d37eogsl6/64089529439.pdfIn PDF document text
    • https://booking-news.hkdnracing.com/webroot/editor-uploads/files/14606396748.pdfIn PDF document text
    • http://architects-desk.com/uploadsfile/82973600729.pdfIn PDF document text
    • http://hairtransplantmangalore.com/uploaded_files/userfiles/files/ripizob.pdfIn PDF document text
    • http://cu-mbc.com/ckfinder/userfiles/files/fositutumasuguwe.pdfIn PDF document text
    • https://kolegium.inaheart.org/upload/files/5045965429.pdfIn PDF document text
    • https://calson.garment-pro.com/ckfinder/userfiles/files/32367500721.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=manualidades+para+regalar+a+mi+novio+facilesPDF 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_off0000e3ba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3BA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fbd1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBD1 11024 bytes
SHA-256: 9ecf1a6f5adfe5d46048568f4ba72659987ade74b97014abe4afa449ad43124b
font_02_sfnt_off00011532.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11532 19212 bytes
SHA-256: ba33f069f619dc138c6511df12703d0ce5df8eadebb05d8cea166468801628d6