Malicious PDF — malware analysis report

Static analysis result for SHA-256 d279f35a1e83ef35…

MALICIOUS

PDF

76.0 KB Created: 2021-09-18 12:52:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 90258dd753bb41a2d03adbd226aa0826 SHA-1: 91684d973a4929690936c1b1638a990bddbadfff SHA-256: d279f35a1e83ef352f7b45cd9946ffa2a0101f8486a12e7dc0210ff7785d4c25
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous URLs pointing to other PDF files, many hosted on compromised CMS sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of multiple unknown PDF links suggests a redirection chain designed to obscure the final malicious payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 http://skontrolsengineering.com/file_media/file_image/file/denuzimopelaf.pdf In PDF document text
    • http://stimatacasa.eu/userfiles/files/tumegibevegama.pdfIn PDF document text
    • https://maintogelonline2.com/contents/files/42362819885.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16142864283995---jadeg.pdfIn PDF document text
    • https://hefcom-hydraulics.com/ckfinder/userfiles/files/80924692504.pdfIn PDF document text
    • http://tuhocxuatnhapkhau.com/uploads/ckfinder/files/rajiriteseguluxaga.pdfIn PDF document text
    • https://jewfri.kr/files/image/files/29706940130.pdfIn PDF document text
    • http://esejsc.com/upload/files/wotidesugabemebavolepidip.pdfIn PDF document text
    • https://my-natural-style.net/upload/files/65341202777.pdfIn PDF document text
    • https://www.hungarianassociation.com/wp-content/plugins/formcraft/file-upload/server/content/files/161429bec79621---31318865942.pdfIn PDF document text
    • https://getlovebooks.com/wp-content/plugins/super-forms/uploads/php/files/6e8d492713fd110dc6cd4764a5189e29/12004358116.pdfIn PDF document text
    • http://www.medical-psychology.gr/wp-content/plugins/formcraft/file-upload/server/content/files/161436fbdd8dd3---saxeje.pdfIn PDF document text
    • https://ncltandatbar.com/home/ncltandat/public_html/dowalumniusa/ckfinder/userfiles/files/moboni.pdfIn PDF document text
    • https://macauroommate.com/ckfinder/userfiles/files/luzadiferaniv.pdfIn PDF document text
    • https://huangs.tw/uploads/files/202109131951565448.pdfIn PDF document text
    • http://skuplaptop.pl/wp-content/plugins/formcraft/file-upload/server/content/files/161402fb00f076---13458603654.pdfIn PDF document text
    • http://bimbrlata.cz/UserFiles/File/30323969287.pdfIn PDF document text
    • https://newshieldinsurance.com/demo/gsa/final/images/file/rujige.pdfIn PDF document text
    • http://www.binghan.my/userfiles/file/jefedoko.pdfIn PDF document text
    • http://christembassydocklands.org/wp-content/plugins/super-forms/uploads/php/files/1b8cca85bd46f24ecc4a7c7f963dc3f5/8379630745.pdfIn PDF document text
    • https://www.caesarstravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a17cd588db---39563550716.pdfIn PDF document text
    • http://satunatc.ac.th/ckfinder/userfiles/files/pubazumuvusimimudakaliti.pdfIn PDF document text
    • http://aurastaffing.es/upload/file/39695799894.pdfIn PDF document text
    • http://bakineshr.az/ckfinder/userfiles/files/nijuk.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=nd+filter+app+for+androidPDF 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_off0000c50d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC50D 10300 bytes
SHA-256: efffbc51078c4a1e9d0d57ab19cd9e9d8d86cbea3d58700ec1fbc8dde06c9f99
font_01_sfnt_off0000dc4a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC4A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f45c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF45C 17844 bytes
SHA-256: 9156a17aaf1fb2af801a7a0e3a68d234ac07244ca7783fd43b5aedf5017b4f3f

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