Malicious PDF — malware analysis report

Static analysis result for SHA-256 a99f6cabcdbc014c…

MALICIOUS

PDF

86.4 KB Created: 2021-07-21 21:45:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 00dfe23449f2e583d637de3b8d5875f6 SHA-1: c86fbef34cdc87a24efc2e06bc434cb37fcf98ac SHA-256: a99f6cabcdbc014c6c85c66a1a4fa8fdf64b3ef9538faa9a1cfdda96de5d6645
156 Risk Score

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier. Static analysis revealed it functions as a link farm, with numerous URLs pointing to compromised WordPress sites. The PDF document itself contains obfuscated binary data rather than readable content, suggesting its primary purpose is to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9984

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 http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/2vcei0eu1cau2me7352sqdn714/97955257627.pdf In PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160900573e7858---fanufolepojimiwuzifuledux.pdfIn PDF document text
    • http://bscartridge.com/pic/87369553914.pdfIn PDF document text
    • http://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607861e350f97---gegibozu.pdfIn PDF document text
    • http://www.redactordecontenidos.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160866c61341b5---jikenodamexitigabixevamu.pdfIn PDF document text
    • https://thejasmineway.net/wp-content/plugins/super-forms/uploads/php/files/v287f9967lc411dseoek7c4img/56890649346.pdfIn PDF document text
    • http://phongkhamthienhoa.vn/images/files/jewibemid.pdfIn PDF document text
    • http://brilspa.ro/userfiles/file///monabezojisodaf.pdfIn PDF document text
    • https://www.qbuildsoftware.com/wp-content/plugins/super-forms/uploads/php/files/e86cead4220f048cb2828df8ce9d15a2/gaganobuniwolabof.pdfIn PDF document text
    • http://www.idenet.net/wp-content/plugins/formcraft/file-upload/server/content/files/160db0ad3552d3---649911767.pdfIn PDF document text
    • http://longearedhounds.com/clients/65743/File/foburixuwodiwifere.pdfIn PDF document text
    • https://parc-hotel.info/file/44225384872.pdfIn PDF document text
    • http://esoftland.com/userfiles/file/12595764846.pdfIn PDF document text
    • https://daaeportrett.no/upload/file/60726944662.pdfIn PDF document text
    • https://saraelv.no/wp-content/plugins/formcraft/file-upload/server/content/files/160c872d122c87---47948009892.pdfIn PDF document text
    • http://trenermichal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1609a62b54a14a---nofikobebobobuda.pdfIn PDF document text
    • https://erinmillssmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/lk2v70gsgdqmmro26fb7j6rjm4/nojojavigakisevav.pdfIn PDF document text
    • https://mnlex.it/file/gozopo.pdfIn PDF document text
    • http://pensionpoint.cz/userfiles/files/29070076105.pdfIn PDF document text
    • http://senseoftourism.dk/userfiles/file/66749839467.pdfIn PDF document text
    • http://www.petersmetalstitching.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1606eedfde0a2b---ramirekabidarajegagudix.pdfIn PDF document text
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/6h064e19d50tc94e18r8r73ll5/rivurukuxijobetaj.pdfIn PDF document text
    • http://dtcguild.org/clients/80367/File/88852611336.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=stretches+for+a+crick+in+your+neckPDF 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_off0000eefd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEFD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001070f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1070F 16648 bytes
SHA-256: 6c4da2581ca04b221a8465d112e864b9473793dcedb621ea0997784b7f1e1f5d
font_02_sfnt_off0001322b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1322B 10768 bytes
SHA-256: a2b0957a316bc4df11d22a7fd4bb144299cb784619d2099ea396d31beb52219f