Malicious PDF — malware analysis report

Static analysis result for SHA-256 19444250d0df8a91…

MALICIOUS

PDF

88.5 KB Created: 2021-09-03 07:48:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: fe83457c168bc0156c0c59b6495344c1 SHA-1: fda8b487e098f8b56aaba8ed07c56010b35b8a0a SHA-256: 19444250d0df8a911ae2db7e8df25414b29c816ecdd6f3f6f37857e0e32a9c1f
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by a machine learning classifier and ClamAV, flagging it as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to compromised CMS upload directories and disposable hosting. These links likely lead to further malicious content or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://cobaltinc.org/userfiles/file/raxoxilo.pdf In PDF document text
    • https://csom.cz/wp-content/plugins/super-forms/uploads/php/files/4e1682dd9ee654d72d8dc525ff3f1abe/45649530688.pdfIn PDF document text
    • http://oipipleszno.pl/userfiles/file/11623127941.pdfIn PDF document text
    • http://avatars.ru/userfiles/file/27775597308.pdfIn PDF document text
    • https://imapcb.org/wp-content/plugins/super-forms/uploads/php/files/f4a4a855733494caddda10eebdc36667/bipegenodedubatiwoz.pdfIn PDF document text
    • http://lindseyderence.com/userfiles/files/palefulida.pdfIn PDF document text
    • http://fittbikese.hu/files/file/petuxamiwuzivuginipilowu.pdfIn PDF document text
    • http://nfraccon.org/userfiles/file/jaduvidisuzej.pdfIn PDF document text
    • http://huefpdf.org/upload/file/tibonizegebugila.pdfIn PDF document text
    • http://roland-toys.eu/userfiles/file/7508073232.pdfIn PDF document text
    • http://banlinhkienlaptop.com/userfiles/file/sevekugubonigo.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae24ce25fcd---silosimejukekumimudumata.pdfIn PDF document text
    • http://uleshuzatshop.hu/files/file/gojumofifokirujip.pdfIn PDF document text
    • http://bpsstudio.hu/uploads/75623205488.pdfIn PDF document text
    • https://www.harasportcenter.com/wp-content/plugins/super-forms/uploads/php/files/tukshd2lueimb8457va1m69d9k/lijilisu.pdfIn PDF document text
    • http://joewhitefamilysite.com/clients/59967/File/45669677686.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1611ea68e7ba5f---17513512093.pdfIn PDF document text
    • https://claudiodituri.it/uploads/86488603719.pdfIn PDF document text
    • http://smcertificationservices.com/userfiles/files/98384098763.pdfIn PDF document text
    • https://www.hdontheroadnapoli.it/wp-content/plugins/formcraft/file-upload/server/content/files/160adcd7f6ee9c---numegojif.pdfIn PDF document text
    • https://alenakovalchuk.ru/wp-content/plugins/super-forms/uploads/php/files/3c583e7265bb206acbc74617b1b9d789/nulasezilef.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=tcpdf+output+filePDF 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_off0000f443.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF443 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010c5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C5A 10140 bytes
SHA-256: 972b6b265e8354ea202340436b401f2ec65c8818efab9077403222d655242518
font_02_sfnt_off00012316.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12316 19120 bytes
SHA-256: d9fefbb5aa00ce3c94b17f401a5c91be283a7fc7b405b4ec8b560b6d019e31bc