Malicious PDF — malware analysis report

Static analysis result for SHA-256 99c738508fc4d0e6…

MALICIOUS

PDF

72.1 KB Created: 2021-09-18 11:13:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 908dafdd69cbde30342ad428b05e0903 SHA-1: 6b14e8991b389d047104001485d34458aa0201cd SHA-256: 99c738508fc4d0e6b573cc656ee1851644e98d8827c85a047a1f3c53841b4eeb
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs pointing to compromised websites, indicating a link farm designed to redirect users. Heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' strongly suggest this malicious intent. The ML classifier and ClamAV detection further confirm its malicious nature, likely serving as a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9902

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://krisoc.ru/uplcv?utm_term=words+on+n PDF link annotation
    • http://cortocircuito.trialpanel.com/images/Upload/files/80923723135.pdfIn PDF document text
    • http://abwhopewell.com/uploads/files/85613758094.pdfIn PDF document text
    • http://sherwoodchambergolf.com/ckfinder/userfiles/files/tuwuxenojuwuse.pdfIn PDF document text
    • http://freestyler.cz/img/file/98693411296.pdfIn PDF document text
    • http://marketingnews.fr/images/file/lebivomavajetupo.pdfIn PDF document text
    • http://adanateknikservis.web.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16140bab5c2d12---bojagokupomebuzerikusako.pdfIn PDF document text
    • http://lionsmarsala.it/userfiles/files/zibawiraniris.pdfIn PDF document text
    • http://impressivetravelvietnam.com/upload/files/40446789324.pdfIn PDF document text
    • http://littlepearlbooks.in/data/eimages/file/kufogarolovofewasuwito.pdfIn PDF document text
    • https://kabelkyaobuv.sk/editor_uploads/files/65102716043.pdfIn PDF document text
    • http://www.cuadernos.in/wp-content/plugins/formcraft/file-upload/server/content/files/1613e91ce2c005---71679575913.pdfIn PDF document text
    • http://twtipa.com/upfile/files/2021/09/03/83047554313.pdfIn PDF document text
    • http://effekt-film.de/files/file/11593344738.pdfIn PDF document text
    • http://annabarons.com/files/files/76274832414.pdfIn PDF document text
    • http://areawifi.com/DESARROLLO/userfiles/files/wumolururemipalabi.pdfIn PDF document text
    • https://ln80.cn/filespath/files/20210908192132.pdfIn PDF document text
    • http://erex.hu/upload/file/84891405983.pdfIn PDF document text
    • http://trust-law-firm.com/userfiles/file/20210917004844_105633207.pdfIn PDF document text
    • http://www.thaitofu.com/image/upload/File/fivila.pdfIn PDF document text
    • http://www.mostex.sk/files/articles/file/25534540330.pdfIn PDF document text
    • https://hopefor.today/wp-content/plugins/super-forms/uploads/php/files/ee1cfe05242464aca14ec22bea110a88/supasikonozodon.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/161316d655c27d---dowaweguzunibelabunibi.pdfIn PDF document text
    • http://atek-ent.com/upload/file/tezaxokezava.pdfIn PDF document text
    • http://gift-founder.com/archive/upload/files/babagusiwijife.pdfIn PDF document text
    • https://zivotzaokny.eu/res/file/fopipoketigaz.pdfIn PDF document text
    • http://tuttotop.com/userfiles/files/2947779487.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_off0000bc8a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBC8A 9704 bytes
SHA-256: 8377845610b6e56700097e27c0be588521bf99310f47226509c3adcbf3ebb70c
font_01_sfnt_off0000d1b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1B9 16128 bytes
SHA-256: 3fafd71f4a3b23a17c95c8be07f15aeed8385e666ca02877729d9d3ab88875a0
font_02_sfnt_off0000fae3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAE3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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