Malicious PDF — malware analysis report

Static analysis result for SHA-256 539d8ace9207724f…

MALICIOUS

PDF

85.4 KB Created: 2021-08-16 11:21:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 160929e053a1308754469a10efea8d2b SHA-1: a7219c9281188db1cdca851e9a276beaccff7549 SHA-256: 539d8ace9207724fc997ec81eff5707a2caf585bee391aa17308b68f598b0f34
156 Risk Score

Malware Insights

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

The PDF contains a large number of external URIs, many of which point to compromised CMS upload directories and disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution through these links. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond what the heuristics reveal.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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 http://tecnoservizi.com/userfiles/files/nepakijanazuseves.pdf In PDF document text
    • https://bowenpainter.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c2e197f1c0---23597869132.pdfIn PDF document text
    • https://granitabrasive.ro/editor_up/45068709931.pdfIn PDF document text
    • http://visualpaint.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fb02fedaf8---1799272332.pdfIn PDF document text
    • https://qualitycountscleaning.com/wp-content/plugins/super-forms/uploads/php/files/5cfb279e9fb766a4e965bd13bcf1bc4b/wizopemu.pdfIn PDF document text
    • http://terapeutickemasaze.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1608b6ff0053de---viduf.pdfIn PDF document text
    • https://olivier-daulte.com/ckfinder/userfiles/files/funexamuvoxed.pdfIn PDF document text
    • http://thetsaban3watnuea.com/UserFiles/file/27407366082.pdfIn PDF document text
    • http://bungefamily.com/clients/5233/File/ruzadekewuvara.pdfIn PDF document text
    • https://pet-fashion.ro/mm/file/61634857023.pdfIn PDF document text
    • https://lederstuehle-shop.de/ckfinder/userfiles/files/33810333853.pdfIn PDF document text
    • http://marthomaiticherukole.com/userfiles/file/gaxupusajumegopikobu.pdfIn PDF document text
    • http://moto-bike.pl/userfiles/file/6588597496.pdfIn PDF document text
    • https://arenda1s.ru/wp-content/plugins/super-forms/uploads/php/files/bb14fc7a3cee5845f914e9e6ac1f0d91/84531221269.pdfIn PDF document text
    • http://nhadatv.com/webroot/img/files/55264670818.pdfIn PDF document text
    • http://probeg2000.ru/files/userfiles/files/39986027567.pdfIn PDF document text
    • http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/g3p30md32nijaf1l7t8s24at70/4376488525.pdfIn PDF document text
    • http://www.majorisinvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160f0766bd622a---11380827588.pdfIn PDF document text
    • http://www.lifestaralberta.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608abc8909f82---fumezo.pdfIn PDF document text
    • http://www.hkqi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072130380127---sudemuzozumepanazu.pdfIn PDF document text
    • https://oceanflowerhotel.com/uploads/image/files/fozajudugos.pdfIn PDF document text
    • https://ludifrance.fr/userfiles/file/3141177776.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=los+7+habitos+de+la+gente+altamente+efectiva+rese%C3%B1aPDF 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_off0000e778.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE778 11344 bytes
SHA-256: aef2440c180a8438734c5cb49b173988f8c0620cbc2473f32a69bd606e5c0480
font_01_sfnt_off00010192.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10192 17100 bytes
SHA-256: 65105e2a1997e120748b03f837b9547140bd8934e3610f8d3e7e6debd280e650
font_02_sfnt_off00012cd7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12CD7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1