Malicious PDF — malware analysis report

Static analysis result for SHA-256 a41dd13df4431cc8…

MALICIOUS

PDF

76.7 KB Created: 2021-10-06 07:53:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 7a23435323a20bbc996a41ab6b2e82cf SHA-1: d90d7813eaf710f7efac17194470ba706cc46687 SHA-256: a41dd13df4431cc84541eca2c87e4b694cfb08cdac86c6e7aa29b4a351ae3218
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for executing malicious code. It also features a large number of external links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious sites or download further payloads. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://queure.ru/uplcv?utm_term=what+do+ph+and+poh+add+up+to+at+25+degrees+c PDF link annotation
    • http://kyea.org/imageuploads/35595574903.pdfIn PDF document text
    • http://www.recko.ru/ckfinder/userfiles/files/92251370148.pdfIn PDF document text
    • https://sf-tfi-pgu.uz/wp-content/plugins/super-forms/uploads/php/files/646d994d7aa81452b3db6662cc81b37b/15884788736.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615108bbdc196---4529598676.pdfIn PDF document text
    • http://titibbs.xyz/js/ckfinder/userfiles/files/toziji.pdfIn PDF document text
    • https://zaragozadenoche.es/upload/files/fofax.pdfIn PDF document text
    • http://air-ned.com/uploads/files/sidubon.pdfIn PDF document text
    • http://sartoriaventurini.com/userfiles/files/25119717495.pdfIn PDF document text
    • http://www.trimbleexpress.sk/wp-content/plugins/formcraft/file-upload/server/content/files/1613190377b96e---89238766027.pdfIn PDF document text
    • http://bortran.com/upload/image/file/20210916092014.pdfIn PDF document text
    • http://www.dfdtrading.sk/ckfinder/userfiles/files/84038789123.pdfIn PDF document text
    • http://choinka4x4.org/cms/files/file/25596801335.pdfIn PDF document text
    • http://evo-models.com/uploads/userfiles/files/nuxubesafedawazidavob.pdfIn PDF document text
    • http://tcgardening.com/userfiles/file/2021090403473573499.pdfIn PDF document text
    • http://www.badischer-kunstverein.de/ckfinder/userfiles/files/65254226510.pdfIn PDF document text
    • https://bank-kredit.at/ckfinder/userfiles/files/gidiwajukafekesi.pdfIn PDF document text
    • https://www.liftechforklifts.com.au/application/third_party/ckfinder/userfiles/files/xumoxewutekejizeb.pdfIn PDF document text
    • https://leicht-spb.ru/wp-content/plugins/super-forms/uploads/php/files/d57a7fb550084b12ad22fda8fc5498e9/30851520607.pdfIn PDF document text
    • http://emailreceptionist.net/userfiles/file/gamofo.pdfIn PDF document text
    • https://fereshtegan.net/basefile/fereshtegannet/files/37672021345.pdfIn PDF document text
    • http://sun-marche.com/app/webroot/js/ckfinder/userfiles/files/31427741358.pdfIn PDF document text
    • http://utuin.net/files/fckeditor/file/gogoguwasu.pdfIn PDF document text
    • http://kmjmt.com/news/upload/file/210929020713882070j4n40k.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_off0000c4f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC4F1 17968 bytes
SHA-256: b8308efce4fd18d55c687837a03c2ef133becce10c5f2ef5385d31de24e28260
font_01_sfnt_off0000f385.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF385 11004 bytes
SHA-256: bc5898fb47b6cecfdbc1f614dc2f918c6f69d7aa32b7ffd80069b41f7a622c9f
font_02_sfnt_off00010cf7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CF7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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