Malicious PDF — malware analysis report

Static analysis result for SHA-256 81c9c27411c2bb19…

MALICIOUS

PDF

83.6 KB Created: 2021-09-20 08:13:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: e42fead8059d7cd4ae4c0025adfcdb13 SHA-1: 279384562a1e79a3fe6f58ad1380f9b451c01974 SHA-256: 81c9c27411c2bb19f4d35b291260afed8a787ff311de1e87926ee6e494a3b8e6
156 Risk Score

Malware Insights

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

This PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs that point to compromised CMS upload storage and disposable hosting, suggesting it functions as a link farm to distribute malicious content or conduct phishing. The presence of multiple external URIs and link farm heuristics indicates a strong intent to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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=android+offline+football+games PDF link annotation
    • https://www.comperat-89.fr/ckfinder/userfiles/files/53675468296.pdfIn PDF document text
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/2942d8d89319e55fceee552a3eb51185/kobomajutifunakojekajokum.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613bba2583209.pdfIn PDF document text
    • http://linker-apps.com/files/jozovesanesof.pdfIn PDF document text
    • https://www.zaantraining.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16135192a9a106---lizijib.pdfIn PDF document text
    • https://www.antoniopopolizio.it/ckfinder/userfiles/files/loxevesiroxugovimukotopil.pdfIn PDF document text
    • https://www.webhisto.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16136e5b79a310---68349963491.pdfIn PDF document text
    • http://hoilhpnqbthanh.com/upload/file/nakasenilifukesumelaf.pdfIn PDF document text
    • https://athensviptour.com/wp-content/plugins/super-forms/uploads/php/files/9cce51740f64903cb5294cc57be5c08f/tisobesowiliputisosozajox.pdfIn PDF document text
    • http://automsystem.com/UploadFile/file/20210918025330124.pdfIn PDF document text
    • http://gelikonline.ru/content/Files/27805766617.pdfIn PDF document text
    • http://carrasvilla.es/uploads/files/pedatasunu.pdfIn PDF document text
    • http://nieruchomosci-swidnica.pl/userfiles/file/35176420626.pdfIn PDF document text
    • https://consultemergingmarkets.cubsindia.com/files/10506775652.pdfIn PDF document text
    • http://corporatiegids.nl/uploads/files/ponun.pdfIn PDF document text
    • http://interface-referencement.com/userfiles/file/gedapubaresu.pdfIn PDF document text
    • http://www.jesuseslaroca.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613244602fe04---nazojomot.pdfIn PDF document text
    • http://bugskin.org/userfiles/file/38958246820.pdfIn PDF document text
    • http://www.restorationservice.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16146cc29cacbe---dodapimifikorenu.pdfIn PDF document text
    • https://stewsites.com/wp-content/plugins/super-forms/uploads/php/files/1440a633ccce306bc73b1e200e17c9c9/rofimijorarifawipedebu.pdfIn PDF document text
    • http://galsabino.it/userfiles/files/32189803540.pdfIn PDF document text
    • https://jills.reviewz.eu/app/webroot/files/userfiles/files/65959193125.pdfIn PDF document text
    • http://stl-hk.net/userfiles/jezovolifuze.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_off0000e56d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE56D 10816 bytes
SHA-256: 0de4e04af7e531a2f09299672bf669a402cc7dbcae4c5a31b264ebb1620f4482
font_01_sfnt_off0000fe21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE21 16432 bytes
SHA-256: 3e5294bc8bb95826d81ab38e4dbc0dfb20a12aad04357925595648bd23ebecb1
font_02_sfnt_off0001289a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1289A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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