Malicious PDF — malware analysis report

Static analysis result for SHA-256 13efe69be2e99a19…

MALICIOUS

PDF

87.7 KB Created: 2021-09-19 23:43:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 31e94876a85b33afb376ec77425e8cfb SHA-1: e7dc5d46d6a429cb9db4543b1c620a4aa6d28c05 SHA-256: 13efe69be2e99a19ec41090e134329b8bd5d87b74e69c695f3257981582a1345
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically indicating phishing and trojan activity. Numerous embedded URLs point to compromised WordPress sites and disposable domains, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true intent beyond the link farm heuristic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://archism.ru/uplcv?utm_term=what+influenced+fashion+in+the+1960s PDF link annotation
    • https://cakesandcupcakes.net/userfiles/files/laguzenurad.pdfIn PDF document text
    • http://scuolascifondocortinadolomiti.it/userfiles/files/pakefenisevomonorisela.pdfIn PDF document text
    • http://lavalnerina.it/userfiles/file/miwipubofixokejol.pdfIn PDF document text
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/16139b7aee596e---muvorokajiro.pdfIn PDF document text
    • http://agrocare.hu/ckfinder/userfiles/files/3015460438.pdfIn PDF document text
    • https://ldoris.com/upfile/files/20210917041651.pdfIn PDF document text
    • https://ww150002.linebot.net/upfile/files/20210915231055.pdfIn PDF document text
    • https://talenthunt.biz/userfiles/file/didanox.pdfIn PDF document text
    • http://remobudostol.pl/pliki/742374910.pdfIn PDF document text
    • http://www.louisefarmersmith.com/admin/ckeditor/ckfinder/userfiles/files/40966136467.pdfIn PDF document text
    • http://mjengo.org/FCKeditor/editor/filemanager/connectors/php/connector.php?Command=FileUpload&Type=File&CurrentFolder=%2Ffile/fixovisawedesab.pdfIn PDF document text
    • http://shopgraeagle.com/ckeditor/uploads/files/92743642667.pdfIn PDF document text
    • https://franchisefarm.franchiseharbor.com/files/files/54989298992.pdfIn PDF document text
    • https://aguiapromocional.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16140ea64473da---kowikozaxagopuzidilidog.pdfIn PDF document text
    • http://danangsculpture.com/uploads/image/files/paxerekug.pdfIn PDF document text
    • http://free-note.kr/files/fckeditor/file/473673487613d53a3ed98b.pdfIn PDF document text
    • http://sriraghavendratemple.com/ckfinder/userfiles/files/6207874615.pdfIn PDF document text
    • http://commandhousecreations.com/uploads/files/86974143981.pdfIn PDF document text
    • http://balashixa.inhome360.ru/admin/ckfinder/userfiles/files/gikaniku.pdfIn PDF document text
    • https://fermuar.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a2d976fb2b---fokeposarokoni.pdfIn PDF document text
    • http://theponghop.com/upload/files/mazorepopikuxer.pdfIn PDF document text
    • https://chokysitohang.com/Uploads/userfiles/files/tuzokitonosejoj.pdfIn PDF document text
    • http://itemclinicchina.com/ckupload/files/91807778211.pdfIn PDF document text
    • http://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613d0d5c053a9---78231736094.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_off0000eff5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFF5 18124 bytes
SHA-256: 1ba52b31ea95f39d38bbba25ae25a756e0db7e1412368c1f3eed57b38da0b50d
font_01_sfnt_off00011ecc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11ECC 11076 bytes
SHA-256: 163b4b11de7db11430408efb0438977a815b85b37099ed463afff7744d22b9f7
font_02_sfnt_off0001388a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1388A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1