Malicious PDF — malware analysis report

Static analysis result for SHA-256 505b43690ffbf87e…

MALICIOUS

PDF

79.5 KB Created: 2021-09-17 09:45:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 07eb952fc847cbba20e1385792dfba4f SHA-1: 7db4d047cc4435bb1020d26b3c86b0e4310dfeb7 SHA-256: 505b43690ffbf87e0600c9cbdd0881960ec334084aaa5bb3e141bb0649d20498
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was identified as malicious by ML classifiers and ClamAV, with heuristics indicating it functions as a link farm pointing to various potentially compromised or disposable hosting sites. The presence of external URIs and link farms suggests an attempt to redirect users to phishing or malicious content, aligning with the 'Pdf.Phishing.Trojan' detection. No scripts were extracted, but the PDF structure itself is leveraged to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://nomylo.ru/uplcv?utm_term=android+add+ssl+certificate PDF link annotation
    • http://www.asap-recruitment.net/upload/file/44142999885.pdfIn PDF document text
    • https://u15.ch/ckfinder/userfiles/files/68260847226.pdfIn PDF document text
    • http://fteq.ru/files/file/10750707108.pdfIn PDF document text
    • http://stopasbestos.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613ecf5f583eb---jejijexikubedif.pdfIn PDF document text
    • https://grupo-kayros.com/userfiles/file/remanetodori.pdfIn PDF document text
    • http://www.juniorcollege.cl/ckfinder/userfiles/files/63661309516.pdfIn PDF document text
    • http://printrun.nl/userfiles/files/fupudifofujekutajofogiz.pdfIn PDF document text
    • http://nasfthr.com/userfiles/file/baladizebarolefodovuviga.pdfIn PDF document text
    • https://mimpisiluman.com/contents/files/pazomenogup.pdfIn PDF document text
    • https://evpersoneli.net/ev-personeli/file/60127096414.pdfIn PDF document text
    • https://ferest.ro/imagini_ws/xoxununamivadud.pdfIn PDF document text
    • https://118highschool.am/wp-content/plugins/super-forms/uploads/php/files/0c0ce18b3c94d920cf7a151672fcebec/9400271885.pdfIn PDF document text
    • http://lenosada.sk/editor_uploads/files/16530012830.pdfIn PDF document text
    • http://saigonradio.com/userfiles/file/rokitine.pdfIn PDF document text
    • http://rsti.biz/files/fck/file/xosowepowek.pdfIn PDF document text
    • http://ontheedgeofnow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139a19bb2d7a---zuwuxojexatijolexo.pdfIn PDF document text
    • https://semangkabiji.com/contents/files/98435112879.pdfIn PDF document text
    • http://sage-chem.com/image/files/20210901_172258.pdfIn PDF document text
    • https://normec-cm.com/ckfinder/userfiles/files/58423942546.pdfIn PDF document text
    • http://bookblog.kr/data/file/files/namobefevimumumibasa.pdfIn PDF document text
    • http://studiophotosfashion.it/userfiles/files/siwurejebiwa.pdfIn PDF document text
    • http://zpb-maciejewski.pl/upload/fck/file/84051907452.pdfIn PDF document text
    • http://istvietnam.com/rich_editor/file/78953276975.pdfIn PDF document text
    • http://restaurant-lyons.fr/userfiles/file/73783492208.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_off0000d2f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD2F6 17616 bytes
SHA-256: 39afef753f17963ab4efb750b238a6abe9d55ce56309a10776ee110bab96fa91
font_01_sfnt_off000100a6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100A6 10448 bytes
SHA-256: e42007dc566c1b49371563b3ba5c48803ea50185369cad73516e6949e5857efe
font_02_sfnt_off0001187b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1187B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1