Malicious PDF — malware analysis report

Static analysis result for SHA-256 51570d940d20a2c6…

MALICIOUS

PDF

75.7 KB Created: 2021-09-09 18:06:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 87a0db78824b77d9a0a49c3bc3f3aa92 SHA-1: 34f276aafd61e8f388626e18613f6ec90b4b9502 SHA-256: 51570d940d20a2c6d8467e9a5f0e9c535794cbbae9ce2bd2cfcca4bef2e41a34
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and a large number of external URIs, many of which point to compromised CMS upload storage or are part of a link farm. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or SEO poisoning. The embedded JavaScript may be used to further obfuscate the malicious links or redirect the user.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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=websites+to+earn+free+robux PDF link annotation
    • https://adikkedua.com/contents/files/donizipabovogutajuxoxa.pdfIn PDF document text
    • https://webgirls-studio.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138dd24bd1f6---48839101939.pdfIn PDF document text
    • https://pragatitic.org/ckfinder/userfiles/files/55955953463.pdfIn PDF document text
    • http://geosond.pl/userfiles/file/22087521562.pdfIn PDF document text
    • https://unicorn.mn/js/ckfinder/userfiles/files/nusimepibiwonakigibusavo.pdfIn PDF document text
    • http://thuonghieutoancau.vn/uploads/files/wowudigaxunuguwumabunik.pdfIn PDF document text
    • http://poexali.org/static/image/_u/system/files/27372016346.pdfIn PDF document text
    • https://izyskately.ru/foto/ck/files/95659061108.pdfIn PDF document text
    • http://paletydozahrady.cz/ckfinder/userfiles/files/piriwilizisos.pdfIn PDF document text
    • https://zhongzing.com/uploads/files/202109070309457975.pdfIn PDF document text
    • http://insightonafrica.in/userfiles/file/redemudojowafigidu.pdfIn PDF document text
    • https://michaels-limo.com/wp-content/plugins/formcraft/file-upload/server/content/files/161377f5291d64---makawupuku.pdfIn PDF document text
    • https://senegal4d.com/contents/files/dekisodep.pdfIn PDF document text
    • http://pobierzplik.pl/uploads/files/balemolowajem.pdfIn PDF document text
    • http://vodova51-53.cz/files/84505327735.pdfIn PDF document text
    • http://ikcem.org/userfiles/file///ridivowinimag.pdfIn PDF document text
    • http://1night2day.com/ckupload/files/9236528413.pdfIn PDF document text
    • http://electric-kernbichler.at/53685610294.pdfIn PDF document text
    • http://sushiyaslo.com/uploads/files/majogufomurafonejubekewum.pdfIn PDF document text
    • http://samnakthodrahassob.com/userfiles/file/71435433934.pdfIn PDF document text
    • http://sooam.com/files/fckeditor/file/205007826461329028a514b.pdfIn PDF document text
    • http://gzhangqin.com/uploadfile/files/kewuvun.pdfIn PDF document text
    • https://www.hospedeagora.com.br/wp-content/plugins/super-forms/uploads/php/files/1gjqu9l953r20bd8ilu3av1vka/16008278073.pdfIn PDF document text
    • https://all-stage-meditation.tw/uploads/files/61350791c5317.pdfIn PDF document text
    • http://abpjse.news-read.com/upload/files/lufurije.pdfIn PDF document text
    • http://www.smwiarus.pl/ckfinder/userfiles/files/29012676940.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_off0000c3df.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC3DF 17348 bytes
SHA-256: 0e0342502750581c6f435b11ebf266ab46f02e318a915dceed7db367ecb28147
font_01_sfnt_off0000f128.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF128 10496 bytes
SHA-256: b1a178747abb8277b1788433eb7406a4f084047eabd3d93aee6196b373807e62
font_02_sfnt_off0001093f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1093F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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