Malicious PDF — malware analysis report

Static analysis result for SHA-256 83916660c752e768…

MALICIOUS

PDF

89.5 KB Created: 2021-09-17 23:03:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 8dafb5773af7f0eee1873e11315536f7 SHA-1: ba538851e327cb65c3811a7cdabbb0d2a0924968 SHA-256: 83916660c752e7689dd077e286baa29e0f73fc2be4677a17dfc45d5501fd90cf
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs pointing to compromised WordPress sites and disposable domains, indicating a link farm designed to lure users to potentially malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with malicious document delivery mechanisms.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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://catamma.ru/uplcv?utm_term=increase+phone+call+volume PDF link annotation
    • http://rujiahk.com/uploadfiles/file/tomefanifosobubetuvid.pdfIn PDF document text
    • http://thesciencenetwork.org/uploads/files/75523102083.pdfIn PDF document text
    • http://yh-nutri.com/filespath/files/20210911201622.pdfIn PDF document text
    • http://www.predoisiasociatii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1612eab4f4369d---mosibasositek.pdfIn PDF document text
    • https://semot.com/Store/userfiles/file/5398916531.pdfIn PDF document text
    • https://www.businesswatchguardingservices.co.uk/wp-content/plugins/super-forms/uploads/php/files/df9la6qbsic9njngq8olnee6pf/zuxomakokod.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/2m83imlupngth32fffr0qe6rbc/99471959805.pdfIn PDF document text
    • https://beauti-full.ru/uploads/files/mekamixige.pdfIn PDF document text
    • http://residencecarlofelice.com/userfiles/files/68101315636.pdfIn PDF document text
    • http://www.yeosung21.or.kr/ckfinder/userfiles/files/1631282069.pdfIn PDF document text
    • https://elminhaj.org/userfiles/file/laxagutusekaw.pdfIn PDF document text
    • https://mai-avto.ru/upload_files/file/suvuwak.pdfIn PDF document text
    • https://controlcert.se/wp-content/plugins/formcraft/file-upload/server/content/files/1612fde5652c7d---8491839932.pdfIn PDF document text
    • https://atx-stroy.ru/wp-content/plugins/super-forms/uploads/php/files/512c0119e0e3ff6431aac2c393ac9d74/17538395009.pdfIn PDF document text
    • http://beauty214.com/uploads/files/202109161635014171.pdfIn PDF document text
    • http://chiron-ventures.com/chiron/home/img/upload/files/210909040347497145sgmp2.pdfIn PDF document text
    • http://webbyshoe.com/fckeditor/userfiles/file/14695918019.pdfIn PDF document text
    • https://gilboamedia.com/userfiles/file/8351150852.pdfIn PDF document text
    • http://spprp.pl/userfiles/file/89463097999.pdfIn PDF document text
    • https://aljazeerahdrilling.com/userfiles/files/98300847074.pdfIn PDF document text
    • http://naphogacomposite.com/upload/files/nilafodefexuf.pdfIn PDF document text
    • http://donovaly-ubytovanie-safran.sk/web/userfiles/file/pogukolexuwolajemufipumi.pdfIn PDF document text
    • http://collegium-connect.nl/ckupload/files/25062418951.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_off0000f60e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF60E 10568 bytes
SHA-256: 9cc0bdc0e235a460fb8d801b953e35700e20b660eb43836349993be9dfbdb0bb
font_01_sfnt_off00010df7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DF7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012609.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12609 19672 bytes
SHA-256: 8ae5514e3f74aac271bd66ab1197f45b50d491d1e81b4c5e02c9d809d9308fc5