Malicious PDF — malware analysis report

Static analysis result for SHA-256 436f85d812fc71c0…

MALICIOUS

PDF

87.7 KB Created: 2021-08-10 18:42:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: e3258088c988ad3c430c523c1a371af4 SHA-1: 42570099fc389d0e8af449ae245ec68ff092ff5f SHA-256: 436f85d812fc71c00632735599c421580dd270fc93c591fb185e99df57771396
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains embedded JavaScript, which is often used to exploit PDF vulnerabilities or redirect users. The presence of a link farm pointing to multiple distinct hosts, some of which are hosted on compromised CMS upload storage, further suggests a phishing or malware distribution scheme. The embedded JavaScript likely facilitates the redirection to these external URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/11e3719d818f5ef68523596bf5c8a48c/xutijowemojabuku.pdf In PDF document text
    • http://dentherapia.hu/files/file/ranimamobogugosesufiwuxu.pdfIn PDF document text
    • http://goodtraefarm.com/ckupload/files/44552714691.pdfIn PDF document text
    • https://amrapalispot.com/userfiles/file/32270245515.pdfIn PDF document text
    • https://3dreamstudios.com/wp-content/plugins/super-forms/uploads/php/files/6c215cfddbccae55d943ca6ea6769fa0/vokokolinuxebafuwebexejas.pdfIn PDF document text
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090b63e422fd---2591144820.pdfIn PDF document text
    • http://naplesredeals.com/userfiles/files/rumuvoged.pdfIn PDF document text
    • http://sakirnoopo.ru/wp-content/plugins/super-forms/uploads/php/files/72413c69f056942d2bf23736fa44640f/65652081088.pdfIn PDF document text
    • https://atcotourismtravel.com/userfiles/file/diniguwirodisexijow.pdfIn PDF document text
    • http://tpdw.pl/userfiles/file/sozawugotozupapulafo.pdfIn PDF document text
    • http://www.mywil.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160a29188ab5e8---16107537628.pdfIn PDF document text
    • https://greenvalleykerala.com/ckfinder/userfiles/files/42903140794.pdfIn PDF document text
    • http://www.evisiontiendaonline.com/ckfinder/userfiles/files/memurawo.pdfIn PDF document text
    • https://jfefood.com/wp-content/plugins/super-forms/uploads/php/files/737aad5c8925bfc0944335407633df82/safekevetanir.pdfIn PDF document text
    • http://aaexpansionjoint.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a221dc992a4---xixolifotupisutep.pdfIn PDF document text
    • http://investin-khj.ir/ckfinder/userfiles/files/97454395396.pdfIn PDF document text
    • https://nolimitscenter.be/peausitive/images/FCKeditor/file/mexibatasajobegomoxo.pdfIn PDF document text
    • http://aeskulap24h.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e3a83a78ac7---junemafuvupawojimuwel.pdfIn PDF document text
    • http://cesnek-vysocina.cz/UserFiles/File/soxerup.pdfIn PDF document text
    • http://blow-w124.com/js/upload/files/monamasa.pdfIn PDF document text
    • https://szelvedojavitasmiskolc.hu/files/files/gozazuwuvomup.pdfIn PDF document text
    • http://scissortailfarms.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076c40502228---21219691123.pdfIn PDF document text
    • https://www.inkfactory.pk/wp-content/plugins/formcraft/file-upload/server/content/files/16100d397f276e---23918172669.pdfIn PDF document text
    • https://visaonline-vn.com/wp-content/plugins/super-forms/uploads/php/files/ol24rbjv6gip8u2m8bha1dicca/71331064763.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=how+much+do+chief+nursing+officers+makePDF 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_off0000f073.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF073 17232 bytes
SHA-256: f0b30a107aebcb50d5edc5450389cd26578932e60847026d60da92e3275c441b
font_01_sfnt_off00011d5e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D5E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013575.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13575 11048 bytes
SHA-256: 024cb96d3a4b0e68ae9f56ee9a7191a096f2d5fd5ccd894425a416d43611abdf