Malicious PDF — malware analysis report

Static analysis result for SHA-256 72c9636f80c77cd1…

MALICIOUS

PDF

86.0 KB Created: 2021-09-18 22:35:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 697c5311dca80776ddf895461f3bc217 SHA-1: 0ccb8058903d54cc15c9f7b5ff9de2cf0413d091 SHA-256: 72c9636f80c77cd1ec5c8701c14744c1dbb1aa95a6bdb7381971c235b90b171a
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories, suggesting a link farm or phishing lure. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but serving as a container for the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://queure.ru/uplcv?utm_term=what+is+default+sms+app+mean PDF link annotation
    • https://jaunimodienos.lt/wp-content/plugins/super-forms/uploads/php/files/2f2kcm1kvkev3gq9c4tinn2sov/85291909968.pdfIn PDF document text
    • http://dr-onesrl.com/userfiles/files/gakimizanililulapan.pdfIn PDF document text
    • http://baove24h.org/upload/files/rogakekixatunalanabureku.pdfIn PDF document text
    • https://hydratrend.com/application/third_party/ckfinder/userfiles/files/lelikaxaro.pdfIn PDF document text
    • https://tivicom.vn/upload/files/4705701685.pdfIn PDF document text
    • https://itscebu.com/upload/file/20210912155453.pdfIn PDF document text
    • http://wwm-quanta.com/upload/files/88433172198.pdfIn PDF document text
    • http://cerrutistudio.eu/userfiles/files/gikezivo.pdfIn PDF document text
    • https://akvanova.ru/sites/default/files/joroworidasazewuxe.pdfIn PDF document text
    • http://salonorganica.ru/upload/files/juranejemuvolarolibopal.pdfIn PDF document text
    • http://chanhbon.vn/media/ftp/file/9640751985.pdfIn PDF document text
    • http://stardentalcare.org/userfiles/file/22798498656.pdfIn PDF document text
    • https://vrindaindia.com/php/joseph/uploads/file/febilazelowuxokisajawi.pdfIn PDF document text
    • https://kurek-rowery.pl/user_pict/file/335884774.pdfIn PDF document text
    • http://mountmedpharmacy.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1613ec35657944---filudodolavikofapologik.pdfIn PDF document text
    • http://zatuchlina.cz/upload/file/22439281796.pdfIn PDF document text
    • http://autosoftware.company/autoresponders_images/files/69334135844.pdfIn PDF document text
    • http://simonide.org/userfiles/file/32205167580.pdfIn PDF document text
    • http://xn--80aafjbaeihgganggf9ajkncugh2a.xn--p1ai/pict/file/27921149995.pdfIn PDF document text
    • https://marmetal.cevhertemizlik.com/userfiles/files/5217573010.pdfIn PDF document text
    • https://clubkdo.fr/img/pics/files/sagojekika.pdfIn PDF document text
    • http://www.hotel-margherita.com/wp-content/plugins/formcraft/file-upload/server/content/files/16143ba284e4da---bododawori.pdfIn PDF document text
    • http://sbnjl.com/userfiles/files/66371815371.pdfIn PDF document text
    • http://sutipatika.hu/userfiles/files/popubimajijevije.pdfIn PDF document text
    • http://teenmag.cz/userfiles/file/8078145155.pdfIn PDF document text
    • https://digireg.it/upload/16012860059.pdfIn PDF document text
    • 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_off0000ebcb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBCB 10636 bytes
SHA-256: de7dda8f7bc17d79f811d2d6a97ff710ac05d72de2e0418a0ab75ce09ba3fc74
font_01_sfnt_off000103eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103EB 18156 bytes
SHA-256: 24a71c5dcd9254b326f01bd5c0387d6b23f5b33ce8bbdbd58ee5226e68d92878
font_02_sfnt_off00013239.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13239 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1