Malicious PDF — malware analysis report

Static analysis result for SHA-256 51d538144af099b0…

MALICIOUS

PDF

75.1 KB Created: 2021-09-18 19:31:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: e4c49205af9a760e7e497744a10a9820 SHA-1: 3531f8556ca93b0f1fe2b1e4da6fc62aedd0f860 SHA-256: 51d538144af099b00ada40c765df75de74cec55be9853546bc044e124e7e7134
164 Risk Score

Malware Insights

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

The sample is a PDF document containing embedded JavaScript and a large number of external URIs, many of which point to compromised CMS uploads or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. The embedded JavaScript is likely used to facilitate the redirection to these malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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.
  • 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.
  • 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://cructi.ru/uplcv?utm_term=android+add+trusted+root+certificate PDF link annotation
    • http://kelvista.lt/images/files/23254204860.pdfIn PDF document text
    • https://ladida.asia/sporlegen/administrator/imagetempfile/53574916984.pdfIn PDF document text
    • https://www.sussexweddingservices.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16131b7da6ca89---bufejiwazinapozij.pdfIn PDF document text
    • http://urdu-hadith.com/survey/userfiles/files/84786163822.pdfIn PDF document text
    • http://www.firengo.com/userfiles/files/41157950656.pdfIn PDF document text
    • https://didaktika.drmix.cz/uploads/files/mufuvavofebutok.pdfIn PDF document text
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ee7b04561e---76033439403.pdfIn PDF document text
    • http://aotwresort.net/ckfinder/userfiles/files/ziwemugam.pdfIn PDF document text
    • http://yotlist.com/uniformkontakt/userfiles/image/files/zosazakegisixozowojatosin.pdfIn PDF document text
    • http://vivo-mebel.ru/upload/file/watajulob.pdfIn PDF document text
    • https://rocksoliddesigns.biz/userfiles/file/welamoxoxubibedanifufos.pdfIn PDF document text
    • https://mma-montessori.com/admin/ckfinder/userfiles/files/48844631256.pdfIn PDF document text
    • http://h-p-n.fr/catalogue_dynamique/file/soruvadovalebudifesabe.pdfIn PDF document text
    • http://kant21.com/userData/board/file/9006592331.pdfIn PDF document text
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/hiqoe62q7udimejkjp6rn1ihsn/24971780539.pdfIn PDF document text
    • http://salsainkonstanz.de/media/files/26654127435.pdfIn PDF document text
    • http://vtracauto.com/wp-content/plugins/formcraft/file-upload/server/content/files/161460ad7c2ac8---92027677946.pdfIn PDF document text
    • http://achilleferolla.it/userfiles/files/nubimu.pdfIn PDF document text
    • https://noble-program.site/js/ckfinder/userfiles/files/75194876456.pdfIn PDF document text
    • http://cgt-fo-csc.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16139432f34592---33398192068.pdfIn PDF document text
    • http://pnktools-th.org/ckfinder/userfiles/files/pelilenilatozutorofuv.pdfIn PDF document text
    • http://giftboxvietthuy.com/upload/ck/files/bovinakopunis.pdfIn PDF document text
    • http://kingtonkatsu.com/uploads/files/diran.pdfIn PDF document text
    • http://cleangroupbd.com/ck/upload/files/kemowanilaronavuzam.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_off0000c109.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC109 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d920.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD920 10504 bytes
SHA-256: 9580d597baa728747cc75f0edaeaf4f0fbff0416b63d8901b669e27cf47c5d05
font_02_sfnt_off0000f127.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF127 17636 bytes
SHA-256: 6f0eb41ef99a573fce5255cfdec4431729ab4c3b95ae37267e4133ded12e2ac2

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