Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c09582ca5be92b1…

MALICIOUS

PDF

73.5 KB Created: 2021-09-20 00:48:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 3e9ca3202d4dedc6acfdd791b5d5a4a4 SHA-1: 18634583f3df7541d1b61eb6481a4834ef8a30fd SHA-256: 4c09582ca5be92b18238f04d541e41f5d1404b2af1e8dceedbd7a4db16f3e497
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, suggesting a link farm designed to distribute malicious content or phish users. The ClamAV detection and ML classifier strongly indicate malicious intent. While no scripts were explicitly extracted, the nature of the URLs and the PDF format itself often leverage JavaScript for redirection or exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://coretry.ru/uplcv?utm_term=themes+for+gboard PDF link annotation
    • https://okinawa4d.com/contents/files/jegofufuwejejopegutebisus.pdfIn PDF document text
    • http://airholic.com/UpFiles/WebEditorFiles/file/bizaxazawavijijupomupi.pdfIn PDF document text
    • http://changrung.com/ckfinder/userfiles/files/wusimexewan.pdfIn PDF document text
    • http://caribsplash.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613cd85956554---66372486363.pdfIn PDF document text
    • http://citranco.com/users/files/69582860641.pdfIn PDF document text
    • https://readandenjoy.ae/userfiles/files/tiwipujafelox.pdfIn PDF document text
    • http://lixupeng.com/uploads/files/nuwimarowawunaxar.pdfIn PDF document text
    • http://ulrike-mayer.de/userfiles/files/nasuluf.pdfIn PDF document text
    • https://vmkstroi.ru/wp-content/plugins/super-forms/uploads/php/files/b9e0f4a84d1e3c3e5747e660d3ef5be5/mivenelumunifukedodabukuw.pdfIn PDF document text
    • https://everestart.com/images/stories/file/53595791869.pdfIn PDF document text
    • https://www.officinadelgustoroma.com/wp-content/plugins/super-forms/uploads/php/files/8884d0baa922a75528ed77a054bc0b54/10688668012.pdfIn PDF document text
    • http://irinka.org/ckfinder/userfiles/files/mirufulu.pdfIn PDF document text
    • http://synphabase.ch/upload/file/33603628124.pdfIn PDF document text
    • http://4bx.pl/public/file/1458300480.pdfIn PDF document text
    • http://trungtamdaykem.vn/Images_upload/files/21566318215.pdfIn PDF document text
    • http://uco-kampen.com/media/files/22038446875.pdfIn PDF document text
    • https://www.hkha.org/ckfinder/userfiles/files/32962778884.pdfIn PDF document text
    • https://free-spirit-city.eu/uploads/wysiwyg/files/sopupepawijivubuge.pdfIn PDF document text
    • http://geodeslaboratori.eu/userfiles/files/susopovetojepojesikujad.pdfIn PDF document text
    • https://takarasushimn.com/userfiles/files/dirizoxewazixiliga.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16140ce5dc218a---donuru.pdfIn PDF document text
    • http://infrabud.eu/fckpliki/file/sewolefok.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_off0000bc2b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBC2B 17200 bytes
SHA-256: 66fb4c74f1cf01af6f494a5f230f2cf554cb2590523cb2fa0a1b4b3aeacc07d5
font_01_sfnt_off0000e912.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE912 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010129.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10129 10564 bytes
SHA-256: 220eda2f01833b33df3a12786ea3bf504ea78d2bad7f696cf91e02d74cf02713