Malicious PDF — malware analysis report

Static analysis result for SHA-256 b91907c0a2c897d6…

MALICIOUS

PDF

74.8 KB Created: 2021-06-26 19:18:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 481336703becbeea908cbd048b9abbcc SHA-1: 44d40f557bb60f7b05796ea4b588327dff71aca6 SHA-256: b91907c0a2c897d6dac0ab973c81e4b8a9f8d737c55041d29961c6e45bf31ee5
164 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Several heuristics indicate the PDF acts as a link farm, pointing to compromised WordPress sites hosting PDF files. The presence of a 'download button' heuristic further suggests a lure to download a payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a15b2d2a862---xitimorax.pdf In PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16084f6711a9cf---67908288473.pdfIn PDF document text
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/160bc4b7812f6f---59845426282.pdfIn PDF document text
    • http://www.belladermeestetica.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16072bc0cdd921---67281227381.pdfIn PDF document text
    • https://www.rowtheerne.com/wp-content/plugins/super-forms/uploads/php/files/d3c4d9e08083a9ed764bece32198222f/27868135413.pdfIn PDF document text
    • http://naasschoolofmotoring.ie/fckeditor/userfiles/file/51082856849.pdfIn PDF document text
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607d7e6f2d2f9---demosagikekirivoparonomu.pdfIn PDF document text
    • http://ambvetbrashersclavoghisu.eu/userfiles/files/gunedenimajobugilejop.pdfIn PDF document text
    • https://brahmagnanam.org/fck_uploads/file/betupogudeliwamakobat.pdfIn PDF document text
    • https://brandonsmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/51lfo0g5go30307ssrgo63pgc6/toxajupeges.pdfIn PDF document text
    • https://www.grandeprairie.org/wp-content/plugins/formcraft/file-upload/server/content/files/16090c55fe4e5d---wokufedixuvuwixesegamur.pdfIn PDF document text
    • http://recamonde.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a945b2e6180---sotinuviwexonipovuwosur.pdfIn PDF document text
    • http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/kh8t3jqafbgjmrb4n8mnvgs3e7/31370453419.pdfIn PDF document text
    • https://deconkhoemanh.com/wp-content/plugins/super-forms/uploads/php/files/dbfmdpik77ihumr48lnjdrfacf/pubizuwalo.pdfIn PDF document text
    • http://ziepniekkalns.lv/wp-content/plugins/formcraft/file-upload/server/content/files/160949175433e7---ruwagobe.pdfIn PDF document text
    • http://gymostrov.org/gymostrov/userfiles/file/8718112224.pdfIn PDF document text
    • https://goldenparadisestsimons.com/wp-content/plugins/super-forms/uploads/php/files/f279378a49959a349e4743c757404fd2/voxuzelegejimepekenadagud.pdfIn PDF document text
    • https://areicon.com/images/file/8345151276.pdfIn PDF document text
    • http://pebyte.com/wp-content/plugins/super-forms/uploads/php/files/ftnjf6vukc055rhm1v9ck1uhqn/38680568344.pdfIn PDF document text
    • http://alpha-th.com/userfiles/file/jegufewi.pdfIn PDF document text
    • http://reclaimsplus.com/wp-content/plugins/super-forms/uploads/php/files/361c7b46f3780a16c175d84d9cfe7a43/fuxolonu.pdfIn PDF document text
    • https://csom.cz/wp-content/plugins/super-forms/uploads/php/files/e9b715aeebdab23dedebae939a96b630/13225048279.pdfIn PDF document text
    • https://www.brightfieldbusinesshub.co.uk/wp-content/plugins/super-forms/uploads/php/files/9l7ac04gd4d2ipn0tc5ldlgh1o/zixojiwesepevuro.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=free+convert+word+document+to+pdfPDF 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_off0000c332.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC332 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000db49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB49 10544 bytes
SHA-256: f2f5ffb0a5d33253dfea2dcf645a20669586ceefa8545e176dcd15efedfb0b3c
font_02_sfnt_off0000f34d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF34D 16640 bytes
SHA-256: b17311a800eedb01a88f9de780d676c93320224aecba41225fd2e1c4904d92b0