Malicious PDF — malware analysis report

Static analysis result for SHA-256 835c4e18279111c4…

MALICIOUS

PDF

96.2 KB Created: 2021-08-12 05:19:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 01be763b265351353a1411ebde33c7f0 SHA-1: d335f518367a78a8dbb7e0bf9d430d18d2bf1cd8 SHA-256: 835c4e18279111c4b5e6480d87f808d1270de672234bada5825a0a30a2b0a94f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs pointing to compromised WordPress sites and other disposable hosting, suggesting a link farm or redirection scheme. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this, indicating the PDF is used to distribute links to potentially malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://crewmak.ru/uplcv?utm_term=guess+the+brand+logo+quiz+game+answers+level+26 PDF link annotation
    • https://www.spoton.pet/wp-content/plugins/super-forms/uploads/php/files/u1mes54u2vb0an05c8pvodkt92/41216778977.pdfIn PDF document text
    • http://jcon-aps.dk/userfiles/file/61394395796.pdfIn PDF document text
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16075a1fff2d76---35008620553.pdfIn PDF document text
    • http://pujcovnanaradi-tvarozna.cz/userfiles/files/11326865959.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/77325430903.pdfIn PDF document text
    • http://bjbtrh.com/files/pic/file/18197243553.pdfIn PDF document text
    • http://aldo-ins.com/userfiles/file/531268188.pdfIn PDF document text
    • https://www.chesapeake-lighting.com/wp-content/plugins/super-forms/uploads/php/files/b8bc219e0f9977d056b74e8cb3de8371/88923285935.pdfIn PDF document text
    • https://apoiotelecom.com/imagens/img_fckeditor/file/99614188992.pdfIn PDF document text
    • http://nutranghongngoc.com/media/ftp/file/tubaworig.pdfIn PDF document text
    • http://www.hypnotiseur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a8d565e1abe---63591224777.pdfIn PDF document text
    • https://www.hadlowsecurityshutters.com/wp-content/plugins/super-forms/uploads/php/files/b862b8040c04bc7a0bb6337ab1658564/voxusaronikiwumijupagujov.pdfIn PDF document text
    • https://doctmcooper.com/userfiles/files/10341653581.pdfIn PDF document text
    • https://amenajarisiconstructii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607d1ca0bfec0---48450336409.pdfIn PDF document text
    • https://beysukonaklari.com/ckfinder/userfiles/files/72034505387.pdfIn PDF document text
    • https://oneremote.ru/wp-content/plugins/super-forms/uploads/php/files/dd37e1041d18ad36858a735ca51711ed/nuwig.pdfIn PDF document text
    • http://chicagohalo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2efc3737c2---begogotiwogil.pdfIn PDF document text
    • https://www.digitalsofts.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bceb248c705---92373710568.pdfIn PDF document text
    • https://hanomanberjaya.com/contents//files/rexajosuravegabafuf.pdfIn PDF document text
    • https://3dreamstudios.com/wp-content/plugins/super-forms/uploads/php/files/c8cd348049320e96c60266fb447a0b8a/burupi.pdfIn PDF document text
    • https://serwisnawigacji.pl/userfiles/file/mijewobumu.pdfIn PDF document text
    • http://beckydavidsonhomes.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c920bd7141f---gatozu.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_off0001103c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1103C 11620 bytes
SHA-256: 99f1f2b8926908d76db605adb438292548cbd66cb9335d6ebcf498452ef92d74
font_01_sfnt_off00012b4e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12B4E 17872 bytes
SHA-256: c975f00714c084d365173780503a6d5d581ef15b2090936f61d1183df2ce1f4d
font_02_sfnt_off00015a31.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15A31 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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