Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4044541c5ad6852…

MALICIOUS

PDF

72.2 KB Created: 2021-09-28 07:19:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 4eea9b2b66d8a367ea6700a3fc0025c4 SHA-1: 4f1b1126d1f31f97741fc68a12ad5c10d6af68d0 SHA-256: b4044541c5ad685220b236c224702790ea9b6a13cc3cffa666adc6aeb9b97ce9
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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=you+are+my+heart+quotes PDF link annotation
    • http://chothuethietbi.info/img/files/24726520020.pdfIn PDF document text
    • https://www.helpfulhunks.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613bd8273bb4f---farowumerabaw.pdfIn PDF document text
    • http://ajej.pretty-match.com/upload/files/37984183954.pdfIn PDF document text
    • http://a2itsolutions.com/chop/multimedia/userfiles/file/57735790994.pdfIn PDF document text
    • https://coebmsf.com/userfiles/file/66622687200.pdfIn PDF document text
    • https://aglogistics-bo.net/userfiles/file/verulorijufoguzute.pdfIn PDF document text
    • https://mimpishio.com/contents/files/gegamelokotiriduwevina.pdfIn PDF document text
    • http://shesob.com/file/files/xefovoxeziwivusidimedif.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/161394d627c026---mivixizenifujuxixepida.pdfIn PDF document text
    • https://soechi.id/userfiles/file/zitipixulexu.pdfIn PDF document text
    • http://verkoop-je-wagen.be/wp-content/plugins/formcraft/file-upload/server/content/files/16144a33876635---tazareguxedudosifaf.pdfIn PDF document text
    • http://lisahyatthealth.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138674591d1d---29354277894.pdfIn PDF document text
    • http://tw-tms.com/uploadpic/xw/files/dumimagadejotox.pdfIn PDF document text
    • http://0985028898.kad.tw/kads/ckfinder/userfiles/files/bipezivorujinawofasosod.pdfIn PDF document text
    • https://jamisonfurnace.ca/userfiles/files/xotinewakalikamujozera.pdfIn PDF document text
    • https://ichapps.com/ichapps/ckeditor-ckfinder-integration/uploads/files/87095148791.pdfIn PDF document text
    • http://abwingscolley.com/uploads/files/10228395687.pdfIn PDF document text
    • http://lotuscourtpune.com/wp-content/plugins/super-forms/uploads/php/files/218e524c528837a56a1b4779cb214a2c/vuvife.pdfIn PDF document text
    • http://dr-temt.ru/images/file/72679079086.pdfIn PDF document text
    • http://jonme.net/ckupload/files/gazuzopovogit.pdfIn PDF document text
    • https://pecsikult.hu/files/file/73429676907.pdfIn PDF document text
    • http://kidsjeodo.com/images/files/gelemiwux.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_off0000b406.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB406 18196 bytes
SHA-256: 87e5807af52f60b12ae8955c701ef481181b4b10f20dcf79c45e053e719365f1
font_01_sfnt_off0000e32d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE32D 10476 bytes
SHA-256: 7aeb872cf49498bb9b78a7489027689c668cdec785bf06748679ed1b9e154ac9
font_02_sfnt_off0000fb18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB18 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1