Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef39d3553e7cd622…

MALICIOUS

PDF

75.6 KB Created: 2021-09-13 18:31:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: b8a969d8063801c7a18eb91545c23f14 SHA-1: 56067754e04574d2d08bbe88a4e78b81a81309d6 SHA-256: ef39d3553e7cd6227e7f1c96850f7a130cb7a65e584d5fdfa59d1ef31b839a07
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 disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. Although no scripts were directly extracted, the PDF structure and URL patterns are consistent with malicious document lures.

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://juvelyrikoscentras.lt/Files/file/kivuw.pdf In PDF document text
    • http://chixue.com/uploadfile/file/20210905014908.pdfIn PDF document text
    • http://3sdent.com/upload/files/41523137797.pdfIn PDF document text
    • http://www.mmd.ntou.edu.tw/ckfinder/userfiles/files/46623355242.pdfIn PDF document text
    • https://htlexpress.com/ckfinder/userfiles/files/tuzodilatakasosok.pdfIn PDF document text
    • https://inwestorfinanse.pl/userfiles/file/botisenebigufasuv.pdfIn PDF document text
    • https://sanruouvang.net/images/uploaded/file/barukirowub.pdfIn PDF document text
    • http://muacuoi.vn/Pictures/files/terap.pdfIn PDF document text
    • http://xn--42cfa4ewb0a0b3fwh.com/imageupload/files/69115234458.pdfIn PDF document text
    • https://recapress.com/ckfinder/userfiles/files/5467287799.pdfIn PDF document text
    • https://hyosungulf.com/uploads/file/fapaxuse.pdfIn PDF document text
    • http://pn-tech.net/userData/board/file/gozarejoranebaliximotim.pdfIn PDF document text
    • https://treasurehunterdetectors.solar-ovens.net/ckfinder/userfiles/files/pifagopaboxasuxawo.pdfIn PDF document text
    • http://ct-tci.com/cttax/userfiles/files/zolakipiwinixewu.pdfIn PDF document text
    • http://elandtour.com/FileData/ckfinder/files/20210902_DF0B0E2ED335947E.pdfIn PDF document text
    • http://erex.hu/upload/file/xiwugumafoloxat.pdfIn PDF document text
    • http://www.acefence.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ec62ac844b---ruziwugixilamuluvuxalupuk.pdfIn PDF document text
    • http://objets.immoweiss.lu/userfiles/files/fijuto.pdfIn PDF document text
    • http://transgusto.ch/userfiles/file/20111969568.pdfIn PDF document text
    • https://huuphongplastic.vn/uploads/images/files/99679389671.pdfIn PDF document text
    • https://givemeit.ru/wp-content/plugins/super-forms/uploads/php/files/b0f26758fbefb163ad76ab735db6c50b/81732691973.pdfIn PDF document text
    • https://zhongzing.com/uploads/files/202109130104037045.pdfIn PDF document text
    • https://glass-haus.ru/wp-content/plugins/super-forms/uploads/php/files/30d273f2f05cca7f6f36e7e463131732/36136033250.pdfIn PDF document text
    • https://ecohort.biz/userfiles/files/67768283857.pdfIn PDF document text
    • http://paletydozahrady.cz/ckfinder/userfiles/files/85449551834.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=b6+12+apkPDF 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_off0000c07c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC07C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d88e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD88E 20216 bytes
SHA-256: 77aa3a2663a9f256fdd51b192bb6adb3e88cc9a09589301931e006d6fefdfaf1
font_02_sfnt_off00010b1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B1A 9868 bytes
SHA-256: add71caa53c06e27ac1ecea4885eb41d7b6d37e81d9cf5d4700ae2ac76b31a88