Malicious PDF — malware analysis report

Static analysis result for SHA-256 a77feb1c87262547…

MALICIOUS

PDF

70.4 KB Created: 2021-09-09 10:27:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 2629f2c9f13da251d0211ab643e4bd66 SHA-1: dcb0fe0e3d801c738c98b6add9e504db8484f0d9 SHA-256: a77feb1c87262547046d5d66696780878ccddf3c48826b652a3a5c106daeb827
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites 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. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' confirms the nature of the links, and the presence of external URIs suggests the document's primary function is to lead users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://krisoc.ru/uplcv?utm_term=react+design+system+library PDF link annotation
    • https://sysyanginguvenlik.com/uploads/files/80597792075.pdfIn PDF document text
    • http://studiofagiani.eu/userfiles/files/86221727549.pdfIn PDF document text
    • https://propbrains.com/wp-content/plugins/super-forms/uploads/php/files/a8b272fede16f79d579f2cd986b493cf/19720812941.pdfIn PDF document text
    • https://monyetmesum.com/contents/files/minekonaso.pdfIn PDF document text
    • https://girisimhaber.com/uploads/file/26596465962.pdfIn PDF document text
    • http://spbmedaks.ru/sites/default/files/uploads/zulapezazinarudewufoza.pdfIn PDF document text
    • https://codecs.ro/images/file/21869910816.pdfIn PDF document text
    • https://houstoncoinshow.org/FCKeditor/file/37861319538.pdfIn PDF document text
    • https://veglifekc.org/wp-content/plugins/super-forms/uploads/php/files/wadojoniziguranufo.pdfIn PDF document text
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613291a8de797---jevuwuw.pdfIn PDF document text
    • http://mamolenasnc.it/userfiles/files/padimowodifovesetakax.pdfIn PDF document text
    • http://studiorapizza.it/userfiles/files/13793566568.pdfIn PDF document text
    • http://pmke.cz/pictures/files/35941573702.pdfIn PDF document text
    • https://vkgnassociates.com/dayafter/uploadimages/newsimages/file/gibaleraxumizowewowegat.pdfIn PDF document text
    • https://areopag.ru/sites/default/files/uploads/10133073770.pdfIn PDF document text
    • http://kleinschadenexpert.com/userfiles/file/nonovowe.pdfIn PDF document text
    • http://rambud.pl/uploaded/file/23963081196.pdfIn PDF document text
    • http://toyotarent.tw/FileData/ckfinder/files/20210904_27A2716304D513F3.pdfIn PDF document text
    • http://kvrhousing.com/uploads/bubegegipivujuligor.pdfIn PDF document text
    • http://saltokisport.com/uploads/files/puzuzemukelipevonutazina.pdfIn PDF document text
    • http://fskyok.com/uploadfile/files/weruwesepamorodupiripufom.pdfIn PDF document text
    • https://marupyara.com/fotos/userfiles/file/pifubolotolunanonefeti.pdfIn PDF document text
    • http://allgeology.ru/ckfinder/userfiles/files/32717842992.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_off0000b19a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB19A 10892 bytes
SHA-256: 76b1007c657ed909dbe7c7a696e28bc3d666f31ae73a827b5db9ed6ef9f62e2b
font_01_sfnt_off0000ca8f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA8F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e2a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE2A1 16104 bytes
SHA-256: 98762c992e068426d085abab207394d72fb39f2be8353605eb5b42b8f816d3a6