Malicious PDF — malware analysis report

Static analysis result for SHA-256 b855a6777ff27226…

MALICIOUS

PDF

70.2 KB Created: 2021-09-28 15:56:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 1e4e4c3c6470c2cc1ea79f10600715d7 SHA-1: 540f125c3b2d5e108a733093957808fc7f84ddc2 SHA-256: b855a6777ff272262b8729150d77dcff77607d4ec626e0a4b2c4d7aece19043a
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file was flagged as malicious by an ML classifier. It contains a large number of external URIs and link farms, many of which point to compromised CMS upload storage or disposable hosting. The document body is heavily obfuscated and unreadable, suggesting an attempt to hide its true purpose. The presence of multiple links, including one with a 'utm_term' parameter suggesting a lure, indicates a likely phishing or SEO spam campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 5

  • 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://synerhu.ru/uplcv?utm_term=free+robux+generator+easy+verification PDF link annotation
    • https://claphamjunction.com.au/wp-content/plugins/super-forms/uploads/php/files/dc4b3781153303cffd9d321aa992913b/vekufagomo.pdfIn PDF document text
    • http://theydeserveastamp.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613b629c03391---93545515447.pdfIn PDF document text
    • http://webs123.com/userfiles/file/73074071827.pdfIn PDF document text
    • http://mauchlineware.com/html/chapelstreet/web/userfiles/files/lusodenegekusolavo.pdfIn PDF document text
    • http://kanizsakran.hu/userfiles/file/61251164768.pdfIn PDF document text
    • https://ahirealty.in/admin/userfiles/files/merufixojotaname.pdfIn PDF document text
    • https://deesudcoolingtower.com/userfiles/file/netajuwitapilebebaxivag.pdfIn PDF document text
    • http://jyjjapan.jp/files/ckeditor/files/deparamigimogaxunetib.pdfIn PDF document text
    • https://kawanmto.org/contents/files/32838078230.pdfIn PDF document text
    • http://kurier48.pl/files/userfiles/file/64820728096.pdfIn PDF document text
    • http://www.julietlandau.com/fckeditor/userfiles/file/52872067624.pdfIn PDF document text
    • http://psychologadamczak.pl/userfiles/file/girisejafize.pdfIn PDF document text
    • https://horgaszvelem.hu/ckfinder/userfiles/files/23827668835.pdfIn PDF document text
    • https://aluvioneschicamocha.sinecsas.com/ckfinder/userfiles/files/1200215943.pdfIn PDF document text
    • https://autosofortkauf.ch/wp-content/plugins/super-forms/uploads/php/files/oj881e82piequelsi4mfbpt8m0/kosazekejakedujotowixova.pdfIn PDF document text
    • http://gsxr.hu/userfiles/file/taparu.pdfIn PDF document text
    • https://digireg.pl/upload/95130526291.pdfIn PDF document text
    • https://krusomying.com/data/file/keritagalewitupisibuto.pdfIn PDF document text
    • https://fotobolfestmeny.hu/mvc/userfiles/file/87044688259.pdfIn PDF document text
    • https://universal4shipping.net/userfiles/file/tusozadotavatibaganomo.pdfIn PDF document text
    • http://jedwines.com/cmsCart/upload/file/63836657922.pdfIn PDF document text
    • https://carparts-fixture.com/file/file/33785570246.pdfIn PDF document text
    • https://beautifullifeuk.com/wp-content/plugins/super-forms/uploads/php/files/8b74ab8d90c3f18a9b5596798d74b634/rametafadibupo.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_off0000af4e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAF4E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c760.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC760 16740 bytes
SHA-256: ba9014663912e09a0cb8379913d6261a0f23a6d83f811677c3a449501c6913c9
font_02_sfnt_off0000f1ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1AC 10964 bytes
SHA-256: a1ca7a5dbe52630ca1e140ae9ac0a409bd13cfa7958c2576340194a3e6635add