Malicious PDF — malware analysis report

Static analysis result for SHA-256 135d03a8bfc130e1…

MALICIOUS

PDF

93.0 KB Created: 2021-07-07 10:59:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 7542b6173d53701402b855d589d9f68a SHA-1: 68c8ffc55d73fa7400579bae4872164a3f42401e SHA-256: 135d03a8bfc130e1f85c0f399f1b0666edf2278aa879cf12115e3b2d19801a43
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs pointing to compromised WordPress sites and other disposable hosting, forming a link farm. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and embedded URLs suggest it's designed to redirect users to malicious sites, potentially for credential harvesting or further payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9935

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://infrive.ru/uplcv?utm_term=sore+throat+and+esophagus PDF link annotation
    • https://thewentworthco.com/wp-content/plugins/super-forms/uploads/php/files/omik9np92e8c44fd4a8kgnnf8t/zemaw.pdfIn PDF document text
    • http://amuseonline.com/absite/userfiles/file/jemowidexusod.pdfIn PDF document text
    • http://ei-windykacja.pl/upload/file/25195359124.pdfIn PDF document text
    • http://czdashan.cn/uploadfile/file/2021051612455573499.pdfIn PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16085a5ea27f48---7186849176.pdfIn PDF document text
    • http://ghinelliarchitettura.it/userfiles/files/33829841994.pdfIn PDF document text
    • http://ahxxzx.com/userfiles/202106/file/50785627822.pdfIn PDF document text
    • http://backyardreleaf.ca/clients/6/6a/6a4eaaf8452764cb6fc14c9064ed0c71/File/sezizoro.pdfIn PDF document text
    • https://www.hungarianassociation.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a93a826a2b0---16919680663.pdfIn PDF document text
    • https://loskutova.site/wp-content/plugins/super-forms/uploads/php/files/a7569dfeabe90a2a5f1fb8fb49a50130/wegapap.pdfIn PDF document text
    • http://belhavenhighschoolalumni.com/clients/13962/File/28536070440.pdfIn PDF document text
    • http://belovosushi.ru/files/mamiwirase.pdfIn PDF document text
    • https://www.partyshuttlebus.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160804df4885cb---7726095791.pdfIn PDF document text
    • https://andana.us/files/files/66034430552.pdfIn PDF document text
    • http://contentworks.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1606f73277faea---9129740207.pdfIn PDF document text
    • https://www.audifonosdoshoydos.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c12d2eefdb9---83641802115.pdfIn PDF document text
    • https://cullinanconstruction.com/wp-content/plugins/super-forms/uploads/php/files/f8s0t9c0513phjk3dftpk7lrad/fimukifugekuduvinoj.pdfIn PDF document text
    • http://www.brennholz-heinlein.de/wp-content/plugins/formcraft/file-upload/server/content/files/16077f282cacb4---18743509153.pdfIn PDF document text
    • http://marathon-gexin.com/Uploadfiles/files/90556414163.pdfIn PDF document text
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/1607da9463fbad---63434818278.pdfIn PDF document text
    • http://tavernadelsnoguers.com/wp-content/plugins/super-forms/uploads/php/files/dde1fed98ac2ff63ca015dec5ea80b27/jexukixixope.pdfIn PDF document text
    • http://www.x454.com/wp-content/plugins/super-forms/uploads/php/files/i86jrv3imt2r4oleg8es2jjm44/zasifigexujulinikeg.pdfIn PDF document text
    • https://www.mixedclass.com.au/wp-content/plugins/super-forms/uploads/php/files/tbpsdrl4itf61lfrjd0i0kjgtn/86094859241.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/0ae7c08931933fb87bfdab39b3738ad8/dunosibe.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_off00010b54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B54 16732 bytes
SHA-256: 99049c63ed38b5620a291852245b8041deb7fb6d8cc26ab3779b7464866df518
font_01_sfnt_off000136a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x136A9 10708 bytes
SHA-256: 25a751fdfe2b869788d2ff42de85fff761481d92eebd8b460902ce1d96c4976c
font_02_sfnt_off00014ef7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14EF7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1