Malicious PDF — malware analysis report

Static analysis result for SHA-256 391f921073b563a4…

MALICIOUS

PDF

96.9 KB Created: 2021-07-19 19:54:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 1ef4cb0c179da39e4cc1e64082b1cd3d SHA-1: 963929fb5a4038e76c4e543414c760ac652f471d SHA-256: 391f921073b563a41c0c73cd414e719c7469132382db6d49a30e2d4dbd6eeab9
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous compromised WordPress sites, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9747

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://dmddsgn.com/wp-content/plugins/super-forms/uploads/php/files/ac5af3af3696602fbee0dc827663e2d0/61002795208.pdf In PDF document text
    • http://applecentervn.com/uploads/image/files/63671711487.pdfIn PDF document text
    • http://vipavtoufa.ru/wp-content/plugins/super-forms/uploads/php/files/065bb4d527ed2fc71197e453d8796e0a/rajakitomidug.pdfIn PDF document text
    • http://cementfeet.com/userfiles/file/xurabivusodoruwun.pdfIn PDF document text
    • https://fetogram.com/images/upload/files/13122945701.pdfIn PDF document text
    • https://vanphongphampmc.com/upload/files/47930971903.pdfIn PDF document text
    • http://pokemom2.com/uploads/files/48627146507.pdfIn PDF document text
    • https://perleyparish.org/wp-content/plugins/super-forms/uploads/php/files/0b6c55b0312a913da75cb64fd5d65ac4/10080583143.pdfIn PDF document text
    • https://gearforfree.com/wp-content/plugins/super-forms/uploads/php/files/i6mvv779666gr5d8pkgnignqr7/50472942477.pdfIn PDF document text
    • https://alrukn.co/userfiles/files/xenurazanuk.pdfIn PDF document text
    • http://www.garriagricola.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c9e13627fb---83730623590.pdfIn PDF document text
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fc7ed2878a---jididazumetiv.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606ed89caaa53---57321452023.pdfIn PDF document text
    • http://matstravel.ru/userfiles/file/xaguvezoli.pdfIn PDF document text
    • http://twfbs.com/ckfinder/userfiles/files/xotogevapakisadepatozed.pdfIn PDF document text
    • http://starlightcelebrates.ca/clients/4/43/43e9139217482d7666ce300faf566241/File/80023156460.pdfIn PDF document text
    • http://erbilsunhotel.com/wp-content/plugins/super-forms/uploads/php/files/vk6p9vt92apq28hdm3j7hfuoc4/76750319803.pdfIn PDF document text
    • http://rld-carbon.ru/file/97429066828.pdfIn PDF document text
    • http://satakantaresort.com/user_img/files/85737690868.pdfIn PDF document text
    • http://passaicvalleyclassof1957.com/clients/44362/File/nezoji.pdfIn PDF document text
    • https://www.varishastalari.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b5d9456e63---tebalegepagonaluv.pdfIn PDF document text
    • http://ks4073.com/file_media/file_image/file/nujigaxifedamezudi.pdfIn PDF document text
    • http://stavebnevyrobky.sk/www/upload/files/pilavujodazixiwavixefuzes.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/16099dad8c6b53---45254069506.pdfIn PDF document text
    • http://suportti.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607376aa56d13---70228944651.pdfIn PDF document text
    • https://ltgtrends.com/wp-content/plugins/super-forms/uploads/php/files/c927de0eeb9b6633539912cef1931afe/tuvodisovak.pdfIn PDF document text
    • http://harasim.cz/uploaded/files/pexew.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=the+croods+1PDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010462.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10462 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011c73.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C73 16092 bytes
SHA-256: 9d5144547e0b729630886a3ad3ce48e7da84b0115899dd9c2390406af6f0fecd
font_02_sfnt_off000131b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x131B4 17364 bytes
SHA-256: d31425d314f8d01a2b5e47cdb79e5886db4c8c9e018e0e0e8faf23bb00ba4c7b
font_03_sfnt_off00015f4e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15F4E 9980 bytes
SHA-256: 45aa4151d0170efc5715f1c076b71801605f91e7d1a5a42333beb5af0973e2a3