Malicious PDF — malware analysis report

Static analysis result for SHA-256 81815fe4f553ce38…

MALICIOUS

PDF

82.0 KB Created: 2021-08-18 18:01:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 10163263141c269e6bd53d4314ab6c8f SHA-1: ad5318b2223e0b1207c9a44eaf625865063aebb8 SHA-256: 81815fe4f553ce3850660d47bc527a6f7117b1607b08d5ed65bf4f07aa276d9b
156 Risk Score

Malware Insights

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

The PDF contains a link farm directing users to multiple domains, several of which are hosted on compromised CMS platforms. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware delivery. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

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://larrialdiak.es/files/galeria/files/tadokijerepimitejojadoz.pdf In PDF document text
    • https://svltv.in/userfiles/files/gifefazinitorikevotevenu.pdfIn PDF document text
    • https://www.truesdalepainting.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bc76e81d226---48719784092.pdfIn PDF document text
    • https://linhngapt.vn/upload/files/11683255616.pdfIn PDF document text
    • https://freedomhypnosisnyc.com/wp-content/plugins/super-forms/uploads/php/files/5eb3c897061e609a33f51fa1689d6e0d/78882695198.pdfIn PDF document text
    • http://duhochmis.com/files/uploaded/files/7876539031.pdfIn PDF document text
    • https://nhachoxebus.com/upload/fck/file/bixugulafawenipep.pdfIn PDF document text
    • http://hk-sai.com/ckfinder/userfiles/files/suwekigaxaravumoroliv.pdfIn PDF document text
    • https://adbadog.com/wp-content/plugins/super-forms/uploads/php/files/4dcbb18671bf9f2540b4e50cdbcb3dc1/38560672157.pdfIn PDF document text
    • http://ewhamd.net/upFiles/ckeditor/files/51114045630.pdfIn PDF document text
    • http://aostavet.it/userfiles/files/54163808310.pdfIn PDF document text
    • http://www.wiz-fac.com/uploadImg/file/jagaziratudati.pdfIn PDF document text
    • http://www.puhito.hu/uploads/11344763329.pdfIn PDF document text
    • http://obasekiestates.com/UserFiles/file/kuzidob.pdfIn PDF document text
    • http://ventilyatsia-v-sochi.ru/ckfinder/userfiles/files/31187158178.pdfIn PDF document text
    • http://ghhs1968.com/clients/5/57/5762190d0a265df614d1f295a7060a42/File/pikezavi.pdfIn PDF document text
    • http://avandcie-energy.com/ckfinder/userfiles/files/85807465725.pdfIn PDF document text
    • https://realestateconnect.us/wp-content/plugins/super-forms/uploads/php/files/vmacippq4607jq8f0niprg5ud3/97320247022.pdfIn PDF document text
    • http://terapie-psi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607d07e37a077---fovowawenasebuvog.pdfIn PDF document text
    • http://irmascaritasdejesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608f28ea17fcf---woniwod.pdfIn PDF document text
    • http://pnlestari.com/visitbali/image/files/10029860673.pdfIn PDF document text
    • https://www.shropshirefurniture.co.uk/admin/ckfinder/userfiles/files/mulurexarazikomalelatanuk.pdfIn PDF document text
    • http://bagpack.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/160a92e7cc3aac---bemugememibavup.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=electromagnetic+spectrum+practice+problems+answersPDF 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_off0000d9ba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9BA 11024 bytes
SHA-256: e66bbb8c4fa63847c474ca01bb684411de2581adf14f7fca939f75d32250e102
font_01_sfnt_off0000f32a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF32A 17480 bytes
SHA-256: 5b2db2fe93ac21eeec55e7f50b4c57ec87fd8364aeda42af13100cf9214b352b
font_02_sfnt_off00012125.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12125 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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