Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4d57d7d185f5364…

MALICIOUS

PDF

79.9 KB Created: 2021-09-19 13:04:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 83a43bec51cc89391247f3df0dcf0d83 SHA-1: d89c0f77d1887590c349ec28a75d5049bd4c39f6 SHA-256: a4d57d7d185f5364057cf31254b8b9525e1654cc9241de87eabbd2513c82f1ae
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs that point to other PDF files hosted on compromised WordPress sites. The ML classifier strongly indicated maliciousness, and the heuristic firings suggest this PDF is part of a link farm designed to distribute further malicious content. No scripts were extracted, limiting the analysis of direct execution vectors.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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://mudateconmigo.cl/wp-content/plugins/super-forms/uploads/php/files/44598727631fcf97dc77dbf39b2d6691/luvesuvaga.pdf In PDF document text
    • http://bkm-market.net/userfiles/file/rarosovidefifuti.pdfIn PDF document text
    • https://podimercrm.com/img/files/fisufonako.pdfIn PDF document text
    • https://onecre.com/images/content/files/96237477735.pdfIn PDF document text
    • http://principessavencanice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c1980cade2---20096703653.pdfIn PDF document text
    • http://carsonpokebar.com/uploads/files/toditinudex.pdfIn PDF document text
    • https://betalinktech.com/blmedia/file/4631388734.pdfIn PDF document text
    • http://phuwangnam.com/user_file/file/wegetepofaref.pdfIn PDF document text
    • http://sarkanyhajo.hu/files/file/wexavaw.pdfIn PDF document text
    • http://www.chubsorn.com/file/files/55919153458.pdfIn PDF document text
    • https://vizzzio.ru/wp-content/plugins/super-forms/uploads/php/files/6db5985503f4743a046ce5310e54f379/ritejeku.pdfIn PDF document text
    • https://bongkartuantakur.com/contents/files/95744210319.pdfIn PDF document text
    • http://magdrywall.com/project-new/christianbook/upload_images/file/48341563725.pdfIn PDF document text
    • https://mbp.hastatis.com/mbp/upload/images/images/upload/ckfinder/74665135761.pdfIn PDF document text
    • https://nhabe.com.vn/ckfinder/userfiles/files/zaximazul.pdfIn PDF document text
    • http://kayamedbursa.com/userfiles/file/50232393568.pdfIn PDF document text
    • https://kheops-so.fr/ckfinder/userfiles/files/49061513337.pdfIn PDF document text
    • https://www.drserapkagan.com/wp-content/plugins/super-forms/uploads/php/files/1smrjaigfl94bqopftggk52kvl/pezutipewelipil.pdfIn PDF document text
    • http://vititanon.com/user_img/files/xeliguxorimiwupatuxev.pdfIn PDF document text
    • http://topbuild.net/content/xuploadimages/file/61020078400.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613339c8268a7---muwafigatitotatir.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=floral+structure+of+maizePDF 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_off0000d55e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD55E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ed75.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED75 10532 bytes
SHA-256: fb50082a9efd42234f01206ac97021f3d1e71e726015593d8583d03cf50f3a01
font_02_sfnt_off00010588.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10588 17412 bytes
SHA-256: a8cefc27150ee0775e05abce2014256a75985ecbc141c88916a9d5f848ed692c