Malicious PDF — malware analysis report

Static analysis result for SHA-256 8987bacfdaf05a63…

MALICIOUS

PDF

73.9 KB Created: 2021-09-15 18:51:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 9cb9b16d2b59d375c6a00561d19335f3 SHA-1: c22b4d016e33bb91bf03d75d9fa220be406c777c SHA-256: 8987bacfdaf05a6347397a6de5a6598e6fe32ea25af9d7d3a2554d394c2ec3a9
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some hosted on compromised WordPress sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

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://crysiq.ru/uplcv?utm_term=free+robux+ball+blast+mod+apk PDF link annotation
    • http://vdadanang.vn/app/webroot/assets/files/24191440388.pdfIn PDF document text
    • http://bacvietexpress.com/upload/userfiles/files/82732675867.pdfIn PDF document text
    • http://hkparkkonutlari.com/image/files/39188053992.pdfIn PDF document text
    • http://sinice-rasy.cz/files/file/24690456178.pdfIn PDF document text
    • https://cplastik.com/data/cms/file/wutobusad.pdfIn PDF document text
    • https://inunekocp.jp/mailmagazine/upload/files/kufasofafugugipowix.pdfIn PDF document text
    • http://citygclub.com/ckupload/files/9918725982.pdfIn PDF document text
    • https://sklep-pinokio.pl/web/uploads/files/nojafopobupuravapalegaru.pdfIn PDF document text
    • http://www.anglometais.com.br/adm/Editor/ckfinder/userfiles/files/5090757513.pdfIn PDF document text
    • http://toroisg.com/public/images/files/wikimatito.pdfIn PDF document text
    • http://cuacuonbinhduong.com/upload/files/35667189237.pdfIn PDF document text
    • https://ibliberia.com/ckfinder/userfiles/files/wesulesirawik.pdfIn PDF document text
    • https://kfk-dekoration.dk/images/uploadedimages/file/tatilebuluwoxonefuxadeb.pdfIn PDF document text
    • https://rent-1.es/ckfinder/userfiles/files/xeruwevawililodenefezuje.pdfIn PDF document text
    • http://dinskayarealty.ru/media/file/favupobunemixig.pdfIn PDF document text
    • https://sevenhillsgroup.net/ckfinder/userfiles/files/kurufuki.pdfIn PDF document text
    • https://internationalmedia.com/userfiles/file/21063487633.pdfIn PDF document text
    • http://greenbiotech.vn/uploads/userfiles/file/rosajoge.pdfIn PDF document text
    • https://aguiapromocional.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16134711c254b7---66295445302.pdfIn PDF document text
    • http://www.rolstoellift.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d7b40b1263---52625878013.pdfIn PDF document text
    • http://chapaconoticias.com/assets/ckfinder/core/connector/php/uploads/files/laroto.pdfIn PDF document text
    • http://achwvs.love-mrt.com/upload/files/digogaguzevenefapoma.pdfIn PDF document text
    • https://www.jemelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/161390ea28aeb1---rewajunovobitaba.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_off0000bbd2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBBD2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d3e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD3E4 17448 bytes
SHA-256: 05eb0738f1541a6d6228b85f65cf9859aee013a20299e384978d5146ac5c1aab
font_02_sfnt_off0001014c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1014C 10768 bytes
SHA-256: f980dab0ec501727d3b9ae997afe184a7cdda04458ddcd28a2cd46829d03882f