Malicious PDF — malware analysis report

Static analysis result for SHA-256 795a5079d57df3e6…

MALICIOUS

PDF

81.3 KB Created: 2021-09-09 23:20:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 2b1ecc53352c3c0b2a4f428bddebdd3b SHA-1: 81d8daa05a156ac9602c88c7d11401fbbf479136 SHA-256: 795a5079d57df3e691456c9bad196bded78b2c730ed64bf0a8c9eac2540c1167
172 Risk Score

Malware Insights

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

The sample is a PDF containing embedded JavaScript, which is a common technique for delivering malicious payloads. Heuristics indicate the PDF acts as a link farm, directing users to external PDF files hosted on various domains, some of which appear to be compromised or disposable. The presence of a visual download button further supports a phishing or social engineering attack pattern. ClamAV detection and ML classification confirm the malicious nature of the file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 8

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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 https://catamma.ru/uplcv?utm_term=real+cricket+17+unlimited+tickets PDF link annotation
    • http://calisnt.com/uploads/files/36462988146.pdfIn PDF document text
    • https://hohsingfiber.com/ufiles/files/44230212970.pdfIn PDF document text
    • http://cathugo-yachts.de/res/wysiwyg/file/50250133481.pdfIn PDF document text
    • http://sententtech.com/file_media/file_image/file/41126075752.pdfIn PDF document text
    • http://myphamlulanjina.com/upload/files/78192108870.pdfIn PDF document text
    • http://aczelzalog.hu/tmp/xovolun.pdfIn PDF document text
    • http://wskinbody.com/data/boardData/files/vipibosi.pdfIn PDF document text
    • http://leap-egypt.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613109927c8e0---34824341796.pdfIn PDF document text
    • http://aimecostruzioni.it/userfiles/files/88055447618.pdfIn PDF document text
    • https://eastmangroup.org/ckfinder/userfiles/files/53434408590.pdfIn PDF document text
    • https://diarch.in/WYSIWYGImage/file/58384167630.pdfIn PDF document text
    • http://xn--9w3b270a7kf.kr/data/editor/file/81654194030.pdfIn PDF document text
    • http://5thaveseniors.org/userfiles/file/refanos.pdfIn PDF document text
    • https://landlorddebtadvisory.com/wp-content/plugins/super-forms/uploads/php/files/feb2750fd38ca2fb20c93f555e15922d/kofogide.pdfIn PDF document text
    • https://apsco.ly/userfiles/files/14115587391.pdfIn PDF document text
    • http://www.kroonzuivel.nl/ckfinder/userfiles/files/11916808622.pdfIn PDF document text
    • https://kolorubursztynu.kolorubursztynu.pl/web/uploads/files/nudisemamot.pdfIn PDF document text
    • https://transmar.biz/ckfinder/userfiles/files/47410883778.pdfIn PDF document text
    • https://michaels-limo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613361f7ba23d---sogifem.pdfIn PDF document text
    • https://reaga.net/js/ckfinder/userfiles/files/gufiwa.pdfIn PDF document text
    • http://esangsok.com/upfile/files/63189204833.pdfIn PDF document text
    • https://giritrademark.com/content_files/files/45004780754.pdfIn PDF document text
    • https://nsstore.mx/ckeditor/ckfinder/archivossubidos/files/16749612810.pdfIn PDF document text
    • 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_off0000d83e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD83E 18056 bytes
SHA-256: f710f6e2f3d05bdf056b07ef429b65b1771bc8de3469ef2abff87186fb2e22b2
font_01_sfnt_off000106c6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106C6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011edd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EDD 10752 bytes
SHA-256: fe1f66fdebf4bb690396e9cec7acc3fb7b4f3b6bae353de8c74a731deef3f32d

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