Malicious PDF — malware analysis report

Static analysis result for SHA-256 28a7e742c66a261e…

MALICIOUS

PDF

84.3 KB Created: 2021-08-19 06:15:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 19bf257b44a91aacca9c48d50ffe88c5 SHA-1: 057f6738cf2575494d079550e7ce748755eadba3 SHA-256: 28a7e742c66a261e0ecaae8537816ae2a17fa2da8cb0f071465b7ac480240fb6
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with numerous external URLs pointing to potentially compromised websites or disposable hosting. The document body is unreadable, but the presence of many links suggests an attempt to direct users to malicious content or for SEO manipulation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9983

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://chhsmahs.com/clients/8/83/83f479e57a8bbaec88b4a04d821ef24e/File/nubonafutitaj.pdf In PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/161108ffdc4ed5---70487231239.pdfIn PDF document text
    • http://tomnhenryanderson.com/clients/8/8a/8a1068334c160bb49438aafe8043afff/File/6010133967.pdfIn PDF document text
    • https://fiambreszav.com/wp-content/plugins/super-forms/uploads/php/files/838dcbcc5281584631728467c278d28e/40481587696.pdfIn PDF document text
    • http://dissanna.com/temp/fckeditor/file/77620766087.pdfIn PDF document text
    • https://funkydrop.shop/wp-content/plugins/super-forms/uploads/php/files/7eb27105d35a6c092e4b7ef0cd03a7b5/wefexumowokixuzapanepa.pdfIn PDF document text
    • https://www.gasserbush.com/wp-content/plugins/super-forms/uploads/php/files/7926b6b6295908760bd315e31428802e/84604646465.pdfIn PDF document text
    • http://alituncer.com/userfiles/file/51165177006.pdfIn PDF document text
    • https://farmstead.tw/farmstead/upload/files/77116927149.pdfIn PDF document text
    • http://etoprosto.ru/ckfinder/userfiles/files/tonudukiwojewisiweto.pdfIn PDF document text
    • https://ekselantechnology.solutions/ckfinder/userfiles/files/kunodadimun.pdfIn PDF document text
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a195f21c67a---92370040182.pdfIn PDF document text
    • https://promocionesnma.com/wp-content/plugins/super-forms/uploads/php/files/116df27cf82d74d6a1ac431b47748474/kumepimadud.pdfIn PDF document text
    • https://markzone.az/wp-content/plugins/super-forms/uploads/php/files/i9haqhpp7ceej1ait6flave6kd/xujesisusepifeni.pdfIn PDF document text
    • https://svltv.in/userfiles/files/kutenerimorimo.pdfIn PDF document text
    • http://candientuvibra.com/images/file/38252965404.pdfIn PDF document text
    • http://nghiencuuykhoa.com/uploads/userfiles/file/67465660224.pdfIn PDF document text
    • http://beerskiboot.de/img/upload/file/10682206588.pdfIn PDF document text
    • https://alakharia.com/public_html/userfiles/file/32264705092.pdfIn PDF document text
    • https://506hlapeta.com/files/file/23271080475.pdfIn PDF document text
    • https://www.inkfactory.pk/wp-content/plugins/formcraft/file-upload/server/content/files/16073948a29f48---buruvopejati.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c09cb0a0bde---9966391369.pdfIn PDF document text
    • https://anyimaker.com/upload/users/files/borunirowavoxuvezore.pdfIn PDF document text
    • https://www.baptistenhardenberg.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607e893bcf7b1---60582316835.pdfIn PDF document text
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/eaac502195079ab4de33290b72570d47/43025644269.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=learning+colors+in+spanish+worksheetsPDF 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_off0000e437.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE437 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fc4e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC4E 10788 bytes
SHA-256: 10b6ba1c5db449df717795dd193b7bb3818060a04ad19b1657dda7220949b2ee
font_02_sfnt_off00011526.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11526 16760 bytes
SHA-256: 12dd2bf9dc214ed9b796db4b6f360729dfb358a0cd4709395db21eec2f58a2f3