Malicious PDF — malware analysis report

Static analysis result for SHA-256 6641c78b76737f04…

MALICIOUS

PDF

75.5 KB Created: 2021-09-09 18:09:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: baf0ada95394ff548b04e7dadda4046c SHA-1: c61b101af57d5b11f6396d3fa336e6e57c64be9d SHA-256: 6641c78b76737f04434fb3c74a6fc8eaad04fd2a2952ce4d0f2186861258b391
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, many of which point to compromised CMS upload directories or are part of a link farm hosted on disposable domains. The presence of these links suggests an attempt to redirect users to malicious content, likely for phishing or malware distribution. No scripts were extracted, but the PDF structure itself is used to host these malicious links.

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://www.huaikrachaohospital.go.th/assets/global/lib/ckfinder/userfiles/files/52548065204.pdf In PDF document text
    • http://shangrilatheshow.com/ckfinder/userfiles/files/90758769445.pdfIn PDF document text
    • http://compufoxmail.com/FCKeditor/editor/filemanager/connectors/userfiles/file/fikuto.pdfIn PDF document text
    • https://interconformity.ro/images/file/89934132466.pdfIn PDF document text
    • http://cephedanismani.com/images/pages/file/27705433727.pdfIn PDF document text
    • https://www.kiemtoandongnghi.com/public/plugins/ckfinder/userfiles/files/36921564466.pdfIn PDF document text
    • https://osikovo.eu/webroot/img/content/files/30664208457.pdfIn PDF document text
    • https://mimpishio1bet.net/contents/files/viravowaditonu.pdfIn PDF document text
    • http://bannermaul.com/userData/board/file/59631922762.pdfIn PDF document text
    • https://www.grecosalesinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/161365e3d150e1---20420135721.pdfIn PDF document text
    • http://africareview.in/userfiles/file/zadalebovumugewapuvavapo.pdfIn PDF document text
    • https://amigo-shop.105h.net/upload/files/56159237936.pdfIn PDF document text
    • https://majubesar.net/contents/files/nesosuravadavabigef.pdfIn PDF document text
    • http://ladna.pl/user_images/file/54918220047.pdfIn PDF document text
    • https://www.orthovision-lublin.pl/ckfinder/userfiles/files/bemegelowipixos.pdfIn PDF document text
    • http://schouteninterieurwerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613867382508d---31284130097.pdfIn PDF document text
    • https://hmradiatoriai.lt/images/files/xomixaxugela.pdfIn PDF document text
    • https://chief-moving.com/editor_upload/file/nuzexebafojatemi.pdfIn PDF document text
    • http://hzxf.com/images/upload/File/29388564898.pdfIn PDF document text
    • https://asset-books.com/userfiles/file/18486993565.pdfIn PDF document text
    • https://www.simcoerecovery.net/wp-content/plugins/super-forms/uploads/php/files/5mj8rmh266r0jv144spoghdtg2/riboragij.pdfIn PDF document text
    • https://velvetskin.pl/wp-content/plugins/super-forms/uploads/php/files/414bf2463f11c05b9229815928c55e48/kadodibum.pdfIn PDF document text
    • http://h-p-n.fr/catalogue_dynamique/file/zafivumawogefomasorug.pdfIn PDF document text
    • http://wronba.com/uploads/wysiwyg/file/39062991070.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=pirate+bay+proxy+in+indiaPDF 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_off0000c568.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC568 16908 bytes
SHA-256: e9c19e4fdb2a6405ff7c578e0cb446bbf3d260e66f857bf0e721b2e4ca7d75b2
font_01_sfnt_off0000f0b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0B2 10528 bytes
SHA-256: 608970f96f0544e9951e4cb49024d121b12f41b5e23c8efce98521f82240f18c
font_02_sfnt_off0001089a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1089A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1