Malicious PDF — malware analysis report

Static analysis result for SHA-256 138c48dc790f3f20…

MALICIOUS

PDF

91.8 KB Created: 2021-07-08 19:50:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 0b29804c877c9c20bd195e6ce8d78896 SHA-1: daac283c38f2612e79fe0eabc414f01b5febe73a SHA-256: 138c48dc790f3f20718b6f9c708f63f579abe830ab7f1fb8ffefe226ad3610b1
96 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which point to other PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS upload storage. The ML classifier strongly flagged this PDF as malicious, suggesting it's part of a campaign to distribute malicious content or manipulate search engine rankings. No scripts were extracted, limiting the analysis of direct execution vectors.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9932

Heuristics 5

  • 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://www.ecostroyservis.ru/File/zomotokaviwetoperosuvogin.pdf In PDF document text
    • http://banghetretruc.com/media/ftp/file/wumuxoxemimipoma.pdfIn PDF document text
    • http://aaexpansionjoint.com/wp-content/plugins/formcraft/file-upload/server/content/files/160adef6b8655b---pusajogizogonoxovit.pdfIn PDF document text
    • http://jfac.kr/ckfinder/userfiles/files/60162353843.pdfIn PDF document text
    • https://www.pal-kont.hu/wp-content/plugins/super-forms/uploads/php/files/7738806db6e19f6076bf3d0ed7f38e66/dupetu.pdfIn PDF document text
    • https://sjalikave.hu/pictures/file/derigidoxedod.pdfIn PDF document text
    • http://allaboutdowney.com/userimages/gipiron.pdfIn PDF document text
    • https://fiambreszav.com/wp-content/plugins/super-forms/uploads/php/files/bd986471d1076e1359537b0a1d4763b0/87605471919.pdfIn PDF document text
    • http://biomassasia.net/data_ed/userfiles/file/21869019237.pdfIn PDF document text
    • http://nfc.soo.jp/file/22326416706.pdfIn PDF document text
    • https://actor-conseil.com/files/file/7268008130.pdfIn PDF document text
    • https://zlato-eu.sk/upload/files/nexarid.pdfIn PDF document text
    • http://top1np.com/ckfinder/userfiles/files/94989076799.pdfIn PDF document text
    • https://www.jahnigterbraak.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160741b342a958---getakeleru.pdfIn PDF document text
    • https://www.unicodesystems.com/wp-content/plugins/super-forms/uploads/php/files/le4p0a10oa20h2816459k1d8d0/51308592471.pdfIn PDF document text
    • https://londonvipchauffeur.co.uk/wp-content/plugins/super-forms/uploads/php/files/f3287c43757b3058129eda4113793611/88670396036.pdfIn PDF document text
    • https://pjkconstruction.ca/images/file/80689824509.pdfIn PDF document text
    • http://antwerp-rentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e6ec1e773ee---38672326009.pdfIn PDF document text
    • https://binhruamuinanobac.com/wp-content/plugins/super-forms/uploads/php/files/5vnflfh7erss05va9pv9gjfqpp/namefedogopoponifeza.pdfIn PDF document text
    • https://specialbrands.gr/wp-content/plugins/super-forms/uploads/php/files/245841fe443271dded40c3ad0fdf4212/3109047329.pdfIn PDF document text
    • http://wskinbody.com/data/boardData/files/xonamoki.pdfIn PDF document text
    • https://cafemocion.com/userfiles/file/ligolizesotef.pdfIn PDF document text
    • http://omgmediatank.com/userfiles/files/34264836688.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=back+and+bi+dumbbell+workoutPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ee01.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE01 16312 bytes
SHA-256: 7d15b2d6d265aaca51dda18faee70a1b8fa9d95ed54cb111fb0895789092f9ae
font_01_sfnt_off00010408.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10408 17172 bytes
SHA-256: e89b9cb06ac32417aa9de0795c1fab93052305f8994f6c29f11f802545267690
font_02_sfnt_off0001304b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1304B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off00014862.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14862 10836 bytes
SHA-256: 1b36399d689cb20877a2e4afb09be4387c5b1b2ec0798f856a1842a1f04fec93

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