Malicious PDF — malware analysis report

Static analysis result for SHA-256 033f33cb10b136e7…

MALICIOUS

PDF

85.4 KB Created: 2021-07-02 08:47:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: e9ea6eb8d7150f97f69a0583311dbf51 SHA-1: 3d8aa2d1d0099237de03a675841ae38bd7f681e2 SHA-256: 033f33cb10b136e79bcdb26147bcdf85eef5ced42d0d769990f6f10bd107d57e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs pointing to compromised WordPress upload directories, suggesting it is part of a link farm designed to obscure the ultimate destination. The primary URL, 'https://cructi.ru/uplcv?utm_term=i+knew+thee+before+i+formed+thee', is likely a redirector to further malicious content. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 6

  • 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.
  • 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=i+knew+thee+before+i+formed+thee PDF link annotation
    • http://recamonde.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160bd3cd81790c---lugakiwipol.pdfIn PDF document text
    • http://www.davidwoodpersonnel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f32301725d---nakurotuvitu.pdfIn PDF document text
    • https://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b7b1356d348---56026327368.pdfIn PDF document text
    • http://www.viksexteriors.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d353f0b9bd---pafijatutogilexakekojas.pdfIn PDF document text
    • http://www.bridalchapel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f0e79c5c69---18505865084.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/pig4vqj2jd7crt3s2o9nf0a5b0/geriletuwop.pdfIn PDF document text
    • https://perfecthospital.org/FCKeditor/file/62027696682.pdfIn PDF document text
    • http://americanpetrochemicals.com/customers/CMS-IMAGES/file/gumupapedibofabow.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/16089ee7777518---59272900631.pdfIn PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/16091bac45d9ee---99073306562.pdfIn PDF document text
    • https://atlanthealth.com/wp-content/plugins/super-forms/uploads/php/files/42dee7ffd91478b07e4c95d9e1198ff7/34285041922.pdfIn PDF document text
    • https://www.avenueroadadvertising.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f0d947dcab---25677279651.pdfIn PDF document text
    • http://www.radioemka.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609348ade0e93---zisexugegisawol.pdfIn PDF document text
    • https://accuratesearch.com/userfiles/file/dalidebemufadipulukokun.pdfIn PDF document text
    • http://beepost.vn/upload/userfiles/files/fasebewoku.pdfIn PDF document text
    • http://azseal.net/uploads/userfiles/file/vosadozikusulezif.pdfIn PDF document text
    • https://fidelishospice.com/ckfinder/userfiles/files/konifofe.pdfIn PDF document text
    • https://adm.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/72b141ef169a7b469b0dea6103418409/lugufurowimusemedin.pdfIn PDF document text
    • https://minutesnap.com/wp-content/plugins/super-forms/uploads/php/files/bed9669372170dbf92d174d5b9abb4bc/32632553474.pdfIn PDF document text
    • https://www.horisunmauritius.com/wp-content/plugins/super-forms/uploads/php/files/65ac23fd4c715c9a83531eba9350f7f6/jolixibamapaxuxogeneguz.pdfIn PDF document text
    • https://slavica.ru/wp-content/plugins/super-forms/uploads/php/files/57f11c7511cf884192482b906f4198bd/lilemogupemigamijis.pdfIn PDF document text
    • https://djennebeads.com/nbloom/fckuploads/file/51890303941.pdfIn PDF document text
    • http://teerosy.com/ipp/images/uploads/files/kurofanivepokeworigenule.pdfIn PDF document text
    • https://service-panev.com/userfiles/44362578310.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_off0000ecd8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECD8 10512 bytes
SHA-256: 12cfe3a1273b1f15701dd65c3c6c6e3318f06595b826390befdcd3e164ce2669
font_01_sfnt_off00010490.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10490 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011ca2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11CA2 16788 bytes
SHA-256: 772e659cc05db488b73ffd17533a0f0b92029cd7fa402d8358a63417e095a8e2

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