Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b4c81005fd1a650…

MALICIOUS

PDF

78.2 KB Created: 2021-07-20 16:15:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: a86ddcffc976b6d39cdb291cbf16c870 SHA-1: 464939bf164e23a4caef51b1f7fff8a1984feabc SHA-256: 4b4c81005fd1a650ad0e4e404289336a87d9cd75e24cd361359eed784a407633
116 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to compromised CMS upload directories. The ML classifier strongly indicates maliciousness, and the heuristic firings suggest this is a link farm designed to redirect users to potentially malicious content. No scripts were extracted, but the primary attack pattern involves luring users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

Heuristics 6

  • 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.
  • QR-code redirect lure medium SE_QR_LURE
    Document instructs the user to scan a QR code with a phone — consistent with QR phishing, but also common in legitimate documents
  • 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://hcs1000.org/wp-content/plugins/super-forms/uploads/php/files/5a34df759e6805ba0392d52724dfab0b/rumaruxezijajazulefab.pdf In PDF document text
    • http://k-sta.kr/FileData/ckfinder/files/20210702_6F95A165DF2B839E.pdfIn PDF document text
    • http://montaze.org/democms/userfiles/file/68859409002.pdfIn PDF document text
    • http://aftckwt.com/uploads/file/33114545550.pdfIn PDF document text
    • https://www.phoenixdentalacademy.co.uk/wp-content/plugins/super-forms/uploads/php/files/2c139f126df6a1e522825bc80a5bee59/rowujefazizizozanuxekipuf.pdfIn PDF document text
    • https://thejinglelab.com/wp-content/plugins/super-forms/uploads/php/files/1ba04nioj7il96ku7sot8o0vdu/2256200891.pdfIn PDF document text
    • https://rebates.forex/wp-content/plugins/super-forms/uploads/php/files/cl6alqaqa45mipili71hjp00l3/zeremumego.pdfIn PDF document text
    • http://kapelski.pl/userfiles/file/jexanamuleti.pdfIn PDF document text
    • http://erbilsunhotel.com/wp-content/plugins/super-forms/uploads/php/files/2897it5equ8407fj1383ugeco1/13434295472.pdfIn PDF document text
    • http://ural-resyrs.ru/data/file/tonitewabe.pdfIn PDF document text
    • http://onlineexpert.in/userfiles/file/88385689942.pdfIn PDF document text
    • https://udachi.co.th/wp-content/plugins/super-forms/uploads/php/files/ga3sbck644erfr42hpru410gfv/zipelufozasedolufurev.pdfIn PDF document text
    • http://asesorialuishervas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072247c138a0---zurawupilom.pdfIn PDF document text
    • http://es-umzuege-transporte.de/wp-content/plugins/super-forms/uploads/php/files/aebbb2218d80e8e216953f5a30a9c1f6/88510331546.pdfIn PDF document text
    • https://him-home.ru/wp-content/plugins/super-forms/uploads/php/files/5135028d3983ee6b1cf43f1f799e3939/20431344995.pdfIn PDF document text
    • http://qtjdb.com/UploadFile/2021/07/05/file/20210705_105242_182.pdfIn PDF document text
    • http://mutamobilya.com/images_upload/files/rejedelazowixezaduv.pdfIn PDF document text
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16070e0b9a71bf---78874428189.pdfIn PDF document text
    • http://velocimapper.com//webfiles/file/gesudugudotulak.pdfIn PDF document text
    • http://sensi-leszno.pl/userfiles/file/fadulagu.pdfIn PDF document text
    • https://www.carlosfunes.es/wp-content/plugins/formcraft/file-upload/server/content/files/1609c6f1adfe40---jaxenafenuwikuwuzuvaki.pdfIn PDF document text
    • http://byty-pardubice.eu/UserFiles/File/detagijebaberaloxapab.pdfIn PDF document text
    • http://portalcom-b2b.es/img/user///file/_0393065001620184294.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=subtraction+sums+for+class+3+with+borrowingPDF 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_off0000cb6d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB6D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e37f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE37F 17360 bytes
SHA-256: 89b0a2dd790a00828c4adb1132aabe6d1a2e48b06c8103f4520912291251c0ab
font_02_sfnt_off00011138.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11138 11224 bytes
SHA-256: db7e379ef4ab8bb25dd610a925e8ea2d7bf580bf994ce7a0c2946089701f4c17

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