Malicious PDF — malware analysis report

Static analysis result for SHA-256 28db54d25019ee81…

MALICIOUS

PDF

99.4 KB Created: 2021-08-25 05:34:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 8b049c8287d6577e42db4a0b57988442 SHA-1: 4dca2443a311ebb34a177304f2deb5927a797162 SHA-256: 28db54d25019ee813d79c7673cd98a17e1831056510796b2cbfb2b735ea01d7a
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as a link farm, with many distinct hosts and links pointing to potentially compromised CMS upload storage. The ML classifier and ClamAV also strongly indicated maliciousness, with ClamAV identifying it as Pdf.Phishing.Trojan. The document body is heavily obfuscated and unreadable, providing no direct clues to its intent beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9986

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://rkdestate.com/userfiles/file/50471496092.pdf In PDF document text
    • http://nfraccon.org/userfiles/file/giwokuriwogalijilesu.pdfIn PDF document text
    • http://ambulatorioveterinariocamali.com/userfiles/files/fidijisunisu.pdfIn PDF document text
    • https://christembassybarking.org/wp-content/plugins/super-forms/uploads/php/files/44f7776edeebbf70d1c66068f8205e28/zadilapadipuworag.pdfIn PDF document text
    • http://bobiniauto.com/userfiles/file/levekuvinofide.pdfIn PDF document text
    • https://oknoplus-omsk.ru/wp-content/plugins/super-forms/uploads/php/files/0ca20beb907ed2c9e44eee1e9fb937b6/69168461240.pdfIn PDF document text
    • http://9meclinic.com/ckfinder/userfiles/files/75200501592.pdfIn PDF document text
    • https://leavereview.com/customerinterview/ckfinder/userfiles/files/soxax.pdfIn PDF document text
    • http://z500.si/files/52934408389.pdfIn PDF document text
    • http://ejmk.com/ej/upload/files/1091089473.pdfIn PDF document text
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f7f437cce21---damadonixamugig.pdfIn PDF document text
    • http://phutungquanghieu.com/app/webroot/files/ckfinder/files/zosebomukevujisagigiwu.pdfIn PDF document text
    • http://hodinovysoused.cz/upload/file/jedimoganulu.pdfIn PDF document text
    • https://aimhc.com/userfiles/file/9514279811.pdfIn PDF document text
    • https://nexusmediation.nl/files/reliwajezetotiwufu.pdfIn PDF document text
    • http://mazurubezpieczenia.pl/zdjecia/fck/file/90449154535.pdfIn PDF document text
    • http://www.hollyskauaicondo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16123c7f7c6607---buvonifatomidavupikorubu.pdfIn PDF document text
    • http://apartamentosalbatros.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073871e5e3d3---xuwotobalojevalikoni.pdfIn PDF document text
    • http://a-range.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1607304025a176---finiwanar.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e2aa79458c8---15269404864.pdfIn PDF document text
    • https://yarpaket.ru/userfiles/file/8850119003.pdfIn PDF document text
    • http://africa-emergence2019.com/userfiles/file/202694498.pdfIn PDF document text
    • https://zanhotel.ro/beficientconsultingFiles/file/nunosasosazo.pdfIn PDF document text
    • http://opalsolar.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607111d361f46---55307770764.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=it+would+hadPDF 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001249a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1249A 9884 bytes
SHA-256: 50af82902aaf8065562adeaf226bde789a46800c7e824162f696e11deb371867
font_01_sfnt_off00013a88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A88 17468 bytes
SHA-256: a7978dc795e259e76d944dfc8ba7e8c037851b947fd115446f9c5e5883d94ee0
font_02_sfnt_off000167f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x167F3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1