Malicious PDF — malware analysis report

Static analysis result for SHA-256 a77cafc0290e3a66…

MALICIOUS

PDF

75.1 KB Created: 2021-10-01 04:10:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: fe03c93ed8457c5e31187b345f5b9c6f SHA-1: 8c3028cf50d5884ccf9058d1b69dda8d94f84ba0 SHA-256: a77cafc0290e3a6683f7ec6bb408355b04db518a10b1e94d05532d323a1a1693
176 Risk Score

Malware Insights

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

The PDF contains numerous embedded URIs pointing to external websites, many of which are hosted on compromised or disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware delivery through these links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but serving as a vessel for the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Clickable URI points to raw IP address medium PDF_URI_IP_LITERAL
    PDF contains a clickable HTTP(S) action whose host is a literal IPv4 address. Legitimate documents normally link to named domains; raw-IP destinations are common in disposable phishing and malware-delivery infrastructure.
  • 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://synerhu.ru/uplcv?utm_term=best+wlan+multiplayer+games+for+android PDF link annotation
    • https://minhgianggroup.vn/upload/files/rasagikugibasuwowukuso.pdfIn PDF document text
    • https://grupa-energia.pl/attachments/file/98501306081.pdfIn PDF document text
    • https://mm-podium.ro/userfiles/file/kigulasovomewebete.pdfIn PDF document text
    • http://xn--o39a91gvwm83kbsn.com/FileData/ckfinder/files/20210908_089228DDB905753A.pdfIn PDF document text
    • https://sahyadrisevasanstha.in/userfiles/file/sudokedijofimoxif.pdfIn PDF document text
    • http://etyekilovarda.hu/userfiles/file/gofegadasonekowukuviz.pdfIn PDF document text
    • https://caribemed.com/userfiles/file/5042400867.pdfIn PDF document text
    • http://showdoimovel.com/files/files/marudetatunevavugufola.pdfIn PDF document text
    • http://ksklinika.ru/ckfinder/userfiles/files/zefikogupidaxupatibegesal.pdfIn PDF document text
    • http://leebyenghun.com/new/upload/board/files/nivurewu.pdfIn PDF document text
    • http://icr34.fr/icr/icr34.fr/www/files/files/25726152550.pdfIn PDF document text
    • http://korealabels.com/ckfinder/userfiles/files/21498475299.pdfIn PDF document text
    • http://0985028898.kad.tw/kads/ckfinder/userfiles/files/dapojofutamadibajewaxeje.pdfIn PDF document text
    • http://dobraukraina.org/sites/all/sites/dobraukraina.org/files/pigiwuruxaxefenexeromepi.pdfIn PDF document text
    • http://amindoost.ir/images/upload/files/vasabikobafoxujus.pdfIn PDF document text
    • http://140.121.180.103/ckfinder/userfiles/files/dixaragujulefubuvalofutub.pdfPDF link annotation
    • http://bitree.net/ckfinder/userfiles/files/87694254060.pdfIn PDF document text
    • https://drainscovers.com/wp-content/plugins/super-forms/uploads/php/files/a3c74267640edb09bd8f310c3de68f14/kukepaparukikusufu.pdfIn PDF document text
    • http://lookupagency.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613d00e7bcbcf---77612693701.pdfIn PDF document text
    • http://backkwang.com/userData/board/file/wanefepuvixojeladov.pdfIn PDF document text
    • https://wurstfargo.com/wp-content/plugins/super-forms/uploads/php/files/92d73bda8b18321c2ffb5b5735c81042/gubipupozowoj.pdfIn PDF document text
    • https://pushtypathshala.com/demo/aims/files/images/files/junufigozejexagerumegoga.pdfIn PDF document text
    • http://zhizhencn.com/filespath/files/20210928040852.pdfIn PDF document text
    • http://lilit-realty.com/wp-content/plugins/super-forms/uploads/php/files/76vk05vf1tgebd703rsp6uqor7/jigujememinatafedix.pdfIn PDF document text
    • http://makesomenoise.hu/upload/file/27978026869.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_off0000b93e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB93E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d150.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD150 18860 bytes
SHA-256: ffa6fde7c5b7ded0d2f93686580146048270091bec21d61ca4b13d578e881760
font_02_sfnt_off00010273.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10273 11196 bytes
SHA-256: cd0a5202c674430fa4a9636026a7fe216872720745a78641b66d8ddc3605ccd0