Malicious PDF — malware analysis report

Static analysis result for SHA-256 81133dba9cdbf849…

MALICIOUS

PDF

157.3 KB Created: 2021-06-29 11:43:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 91b0f9723ef3f7602fb051d7f75b2ae1 SHA-1: 502724043201043abb26814910447b229a600c34 SHA-256: 81133dba9cdbf849678f583575bd5ab3a4fcba08f871e7a00fca2bb2bdce8a02
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links, many pointing to compromised WordPress upload directories, suggesting it's designed to lead users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct textual clues about its intent beyond the presence of embedded URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

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://www.avenueroadadvertising.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608962a1dd57b---ganigatatumo.pdf
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1608346d8686ad---zawusexitimaliz.pdf
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/83ca8721c5d05fb59e659928f40acd16/pozapikazujukawisirumesu.pdf
    • http://www.advancedevents.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16082db939e70e---20818448768.pdf
    • https://samarpanbharat.org/trila/userfiles/file/36751418309.pdf
    • http://mysistermyfriendministries.org/clients/85776/File/93515150691.pdf
    • https://ilc.ua/wp-content/plugins/super-forms/uploads/php/files/heh8ihfg16p5okrninvq6btok4/sexelaw.pdf
    • http://schouteninterieurwerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16079f8bc0e753---lanetivan.pdf
    • https://levin-dent.ru/wp-content/plugins/super-forms/uploads/php/files/bdb2994f37ab1fcfb2b5f2dbd7700287/74477494247.pdf
    • https://www.endthestigmacounselling.com/wp-content/plugins/super-forms/uploads/php/files/oon287c1m2ub6ndkehrqg24nbe/vapufobon.pdf
    • https://catbasailing.com/upload/fck/file/45587957905.pdf
    • https://robertmatzuzi-massagetherapist.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16086719c82700---lotumonutemel.pdf
    • http://webatnet.de/ckfinder/userfiles/files/98901589406.pdf
    • https://frontiersneurophotonics.org/wp-content/plugins/formcraft/file-upload/server/content/files/1/16076c3a3ab2cc---kanefiwesunitamawulivuf.pdf
    • http://tutaylamhet.com/storage/ckfinder/files/1666368831.pdf
    • https://www.quatainvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ad68eb9d5a2---78091082067.pdf
    • https://businesslife.com/content/file/63653623898.pdf
    • http://www.canadiantreasurer.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d4d03804b9---juxufowined.pdf
    • http://www.jhannahs.com/wp-content/plugins/formcraft/file-upload/server/content/files/16096d18046ef1---zaxosejuzedudutojopib.pdf
    • http://www.etoiles-recrutement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b838733e3be---saxujafolifuzegor.pdf
    • https://www.tctnanotech.com/wp-content/plugins/super-forms/uploads/php/files/a8af76f5e6494ae0a15d7a294a0e209e/86214893128.pdf
    • https://spaslask.pl/wp-content/plugins/super-forms/uploads/php/files/9i6vfng50fbskl043vs1sgidkl/likeravebunurepipadade.pdf
    • https://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/9abe0708a39ef4c884b8844430c6b5bf/24322910843.pdf
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ab0da2a5a6---bipakuzesomise.pdf
    • https://funkydrop.shop/wp-content/plugins/super-forms/uploads/php/files/c5d99b1b55cb2cce1caa35648f2dbccb/guzefale.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=proverbs+4+commentary
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00020beb.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x20BEB 16792 bytes
font_01_sfnt_off00022402.bin
81acb45e23774324fecf6b8e8c29ac229b9e98427e74648b8bb8e8ed1d976dec		 pdf-font-stream PDF embedded font (sfnt) at offset 0x22402 10652 bytes
font_02_sfnt_off00023c8d.bin
5fb5fed2f5405bd702a7ab3592cf783e804bdff8d9fca0bfa39499f4f76dbc8b		 pdf-font-stream PDF embedded font (sfnt) at offset 0x23C8D 16684 bytes

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