Malicious PDF — malware analysis report

Static analysis result for SHA-256 e51d3b0d90241373…

MALICIOUS

PDF

82.9 KB Created: 2021-09-13 01:10:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 5f351ced6fd8aa5ce621c350332a84da SHA-1: 096bb7a92a0ab051ad5b9a0d3ad998cf99d1f78b SHA-256: e51d3b0d902413735d70eb1618aeeb7cf706b9050ae67d6ee3f593d24a7f6eb4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It functions as a link farm, with numerous embedded URLs pointing to external sites, some of which are hosted on compromised WordPress upload storage. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

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 http://hanmih.com/userfiles/file/20210907060712.pdf In PDF document text
    • https://greenturtleproductions.com.au/wp-content/plugins/super-forms/uploads/php/files/d93a44eff15a1c3036bc9ebe0c5342c6/solopuwinixujusebiwodelij.pdfIn PDF document text
    • https://autoprofi.ua/userfiles/file/46262452686.pdfIn PDF document text
    • http://cnzhongkui.com/fckeditor/editor/filemanager/connectors/php/uploads/file/020658091161.pdfIn PDF document text
    • https://curewelldiabetes.com/userfiles/file/fuwarupapuritotat.pdfIn PDF document text
    • http://fatename.com/uploads/files/202109060626288208.pdfIn PDF document text
    • http://n3ss.ro/ckfinder/userfiles/files/zozosokox.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16137803004067---16991039476.pdfIn PDF document text
    • https://ermolino.mebel18.com/uploads/files/60292104353.pdfIn PDF document text
    • http://sbcnepal.com/images/file/wilexaponowisiginolotoj.pdfIn PDF document text
    • http://marikitaberbagi.com/userfiles/file/gojuv.pdfIn PDF document text
    • https://monamifrance.com/FileData/ckfinder/files/20210913_5822F4FCDD34686F.pdfIn PDF document text
    • https://hediyelikhanem.com/calisma2/files/uploads/77214074192.pdfIn PDF document text
    • https://ivfnna.gr/wp-content/plugins/super-forms/uploads/php/files/a2163d0c9204eeb806a50b2c2182c43b/piwugugotuzezanumunuxepez.pdfIn PDF document text
    • http://npxbyy.com/wang3_3_10_27/Upload/Upload/file/202194949556547.pdfIn PDF document text
    • https://www.renfrewareahealthvillage.ca/ckfinder/userfiles/files/41667590105.pdfIn PDF document text
    • http://digjamaica.com/app/webroot/files/retejenuguxibemewugedemet.pdfIn PDF document text
    • http://ggbris.com/slbdavbatala/userfiles/file/72922893087.pdfIn PDF document text
    • http://dentalcenterstudio.it/userfiles/files/lofov.pdfIn PDF document text
    • https://kurashi-kyoiku.com/cms/dat/upimg/file/wiwapugolavirugewuj.pdfIn PDF document text
    • http://lex-ter.ru/admin/ckfinder/userfiles/files/jepevu.pdfIn PDF document text
    • http://cuboni.com/uploadfile/hong202109070043246187.pdfIn PDF document text
    • http://voszveszprem.hu/_user/file/2343395258.pdfIn PDF document text
    • http://geometrabottero.it/userfiles/files/5142246007.pdfIn PDF document text
    • https://conviviodihera.it/dati/upload/file/lobutezafexuredeterujit.pdfIn PDF document text
    • https://wct.goldcrownresort.com/magazine_files/files/rifopezenosaxumopipote.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=live+wallpaper+iphone+5PDF 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_off0000dfbb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFBB 18208 bytes
SHA-256: 5269b8fa178258209db9bb34e292a138785a7cab0f83dd5a61d6917952d49e24
font_01_sfnt_off00010f01.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F01 10324 bytes
SHA-256: ec8a9f17f628b971a8c4c28f69ea4c39f7457e4b78bcb4bfe94423bafd7f70c9
font_02_sfnt_off00012640.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12640 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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