Malicious PDF — malware analysis report

Static analysis result for SHA-256 c81fbab34b811f63…

MALICIOUS

PDF

112.8 KB Created: 2021-07-25 08:44:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: f79e914c3ce56d9a1333120509e3d80f SHA-1: 4f787f65806c89c9ae8d6db610b1fe9cfc6e187c SHA-256: c81fbab34b811f635b61f35220ba56a0b0d9eadaae8a4c31de144024e5414fda
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Several heuristics point to the PDF being a link farm hosted on compromised websites, designed to redirect users to potentially malicious content. The presence of embedded URLs further supports the attack pattern of luring users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9863

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://www.heainc.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c125af1f19f---nexanotudir.pdf In PDF document text
    • http://zpb-maciejewski.pl/upload/fck/file/70165590625.pdfIn PDF document text
    • http://adoriantarla.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1609af87cd9920---69478587387.pdfIn PDF document text
    • http://yjsyrj.com/userfiles/file/23566917393.pdfIn PDF document text
    • https://ethiquedevelopers.com/wp-content/plugins/super-forms/uploads/php/files/252a89eb7d58981f9384f6be413c1273/76628655646.pdfIn PDF document text
    • https://globalclassic.org/wp-content/plugins/super-forms/uploads/php/files/4u9fasdnkqqemp8hg2hvfusjvt/guvanewatutaga.pdfIn PDF document text
    • https://www.phoenixdentalacademy.co.uk/wp-content/plugins/super-forms/uploads/php/files/7f357896ff148c4edf22c04aa2a52c82/82637786713.pdfIn PDF document text
    • http://otelm4b.ru/admin/ckfinder/userfiles/files/44356450877.pdfIn PDF document text
    • http://mega.kz/media/upload/files/73243756074.pdfIn PDF document text
    • https://liur-krd.ru/userfiles/file/67040278491.pdfIn PDF document text
    • https://precisionautoandac.com/wp-content/plugins/super-forms/uploads/php/files/188fd651a404a8a694cba6ea12a77b28/ridujatemuxoxalorakiw.pdfIn PDF document text
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d469a3d615c---85104810695.pdfIn PDF document text
    • http://alibabashipping.com/userfiles/file/xoxamulubo.pdfIn PDF document text
    • http://dulichtantai.com/files/uploaded/files/jofikogogan.pdfIn PDF document text
    • https://binarbaidequipment.com/public_html/userfiles/file/26681148594.pdfIn PDF document text
    • http://cerrutistudio.eu/userfiles/files/44515768760.pdfIn PDF document text
    • https://www.xcelsus.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b869898357d---xerigogotupowapevakaluxe.pdfIn PDF document text
    • http://murielbellhomes.com/userfiles/files/22780228301.pdfIn PDF document text
    • https://www.fifatravels.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ee24a846a78---poxaru.pdfIn PDF document text
    • http://nature-revive.org/files/file/47183279546.pdfIn PDF document text
    • https://www.gsccn.it/wp-content/plugins/formcraft/file-upload/server/content/files/1607aa55075a35---19789195228.pdfIn PDF document text
    • https://www.edutechusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160993ae72f6c1---3572359374.pdfIn PDF document text
    • http://calliopegoodrich.com/clients/73417/File/97082406057.pdfIn PDF document text
    • https://www.davidwoodpersonnel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071e8956f265---kalotefejiminamusonova.pdfIn PDF document text
    • http://blackivy.pl/userfiles/file/34339317977.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=math+6%2F7+notes+%285.4%29+translating+verbal+phrases+to+algebraic+expressionsPDF link annotation
    • http://e1pl2.nazwa.pl/busy/fotki/file/pipezakixinaxojajuvesu.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_off00014ff4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14FF4 11640 bytes
SHA-256: 5209c08d93b101156106a35b7d03cef1d95cf464c6d99c6986f73585f2971105
font_01_sfnt_off00016bbb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16BBB 18320 bytes
SHA-256: de39e85ad1f395321c26a9a31b63fce0ebda0faa1e189a70c0fe2a76d1f3ad27
font_02_sfnt_off00019b3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x19B3B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1