Malicious PDF — malware analysis report

Static analysis result for SHA-256 853d87be6a7d4a2a…

MALICIOUS

PDF

76.7 KB Created: 2021-09-07 12:34:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-29
MD5: ef04dbdf9caa1ae9f0ac83f65c04d405 SHA-1: 0f80fe67b3bd490e4e4726d4e2ed6c1bde06c68d SHA-256: 853d87be6a7d4a2a92085b6ea8dfd6fe4a5e94c04e5586deeb6c59f7d73ef741
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or are part of a link farm hosted on disposable domains. ClamAV detected this file as Pdf.Phishing.Trojan, and the ML classifier also flagged it as malicious. The presence of these links suggests the document is designed to lure users to malicious sites, likely for phishing or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://chcial.ru/uplcv?utm_term=equivalent+fractions+worksheet+ks2+pdf PDF link annotation
    • https://greyquotient.com/wp-content/plugins/super-forms/uploads/php/files/e46253bcbb8a608dc7e4bfb0db10347c/26045046290.pdfIn PDF document text
    • http://skuplaptop.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160a72c9da89f0---24381302796.pdfIn PDF document text
    • http://inspirationallabels.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607fc47e53412---zilebasob.pdfIn PDF document text
    • http://hoanhaochemical.com/uploads/files/46620250304.pdfIn PDF document text
    • https://advance-pack.com/editor_upload/file/rutusuxixevudebajotazogew.pdfIn PDF document text
    • https://bazab.ru/ckfinder/userfiles/files/diwovak.pdfIn PDF document text
    • http://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/5391e3136891f6f6912e6ac684c1644a/bivejunudipoladejiserori.pdfIn PDF document text
    • http://1yunnan.com/ckfinder/userfiles/files/85409105475.pdfIn PDF document text
    • https://ahi.com.ua/wp-content/plugins/super-forms/uploads/php/files/4bff1f562fb96ce2644b78518f823d88/39842227433.pdfIn PDF document text
    • http://huerural.com/uploads/image/files/67629451505.pdfIn PDF document text
    • http://firegallery.ru/img/upload/nelipurufiwov.pdfIn PDF document text
    • https://www.treehousecare.org/wp-content/plugins/formcraft/file-upload/server/content/files/160748a2b4a653---48607155450.pdfIn PDF document text
    • https://massagetheory.ca/wp-content/plugins/super-forms/uploads/php/files/6050aa40ca849fe1ef9f29c2d4f65f60/jimeluxomekusuregoxajusu.pdfIn PDF document text
    • http://wypelnienia.kratex.pl/wp-content/plugins/super-forms/uploads/php/files/bca4a2a0920cc5c620e2df81a3736926/96431358048.pdfIn PDF document text
    • https://csodamalom.hu/files/files/kebefubuxuxojujaworekopiv.pdfIn PDF document text
    • https://storage-in-motion.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608dfdec214e3---jilixabiwawedewobimep.pdfIn PDF document text
    • https://afanasyev-design.ru/wp-content/plugins/super-forms/uploads/php/files/4af38b496d9ec1428c7e86d572d8c615/wasoxivi.pdfIn PDF document text
    • https://expresstestingatl.com/wp-content/plugins/super-forms/uploads/php/files/e147b9c8e2d1e0a45a7de0c4720af8c3/57309984962.pdfIn PDF document text
    • https://movesforfree.com/wp-content/plugins/super-forms/uploads/php/files/i5cb590g6m1fre4dkpkepian62/pikipafujukopado.pdfIn PDF document text
    • http://brkvinc.com/userfiles/file/vizawitiluxevuda.pdfIn PDF document text
    • https://ocvirapuato.com.mx/wp-content/plugins/super-forms/uploads/php/files/96cb1d72996eabc427c8e542048aabdd/riwitikiwobuwasifiwexose.pdfIn PDF document text
    • http://winterwonderlandzundert.nl/uploadimages/files/gelodojix.pdfIn PDF document text
    • http://ap116.ru/userfiles/file/57194634048.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_off0000c6e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC6E1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000def3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEF3 16916 bytes
SHA-256: 2f87f980d706798ca5e0e101392abe3ada441a3444464a3aa1fcc747656f8eb5
font_02_sfnt_off00010a7a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A7A 11308 bytes
SHA-256: 6324af1d99b8c509f0e385eb3131b6a666ada0fdc8e7d50e2d1a4aa0d63c7776

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