Malicious PDF — malware analysis report

Static analysis result for SHA-256 a31fd446916d6e8c…

MALICIOUS

PDF

70.8 KB Created: 2021-09-26 07:54:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: a81f4fc3a3f9049be1e2d7871ed23f45 SHA-1: f1337a5a465974649e5547decaf8a26750f014ee SHA-256: a31fd446916d6e8c5bb1bbab12699584f7177556e31b8c95991cd75e883ca13b
156 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external URLs, many hosted on compromised or disposable domains, suggesting a link farm designed to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this, pointing towards a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://catamma.ru/uplcv?utm_term=nba+2k17+mobile+download PDF link annotation
    • https://penzionradvanice.cz/res/file/nibowugitukexe.pdfIn PDF document text
    • https://chief-moving.com/editor_upload/file/fumefupure.pdfIn PDF document text
    • http://elitakhealing.com/ckfinder/userfiles/files/22913280788.pdfIn PDF document text
    • http://ggbris.com/slbdavbatala/userfiles/file/42717075322.pdfIn PDF document text
    • https://www.channeloflove.com/ckfinder/userfiles/files/sakilojejugetitepit.pdfIn PDF document text
    • http://larben.cz/media/images/upload/file/jimerazesazimitet.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/a48416dcd3fdbd82b0ef6576272a7855/lakedup.pdfIn PDF document text
    • http://www.roosprommenschenckelfoundation.nl/ckfinder/files/files/xapitoj.pdfIn PDF document text
    • http://hermandadperdon.es/userfiles/file/pewagugeb.pdfIn PDF document text
    • https://www.benkorner.nl/admin/library/ckfinder/userfiles/files/12763485872.pdfIn PDF document text
    • http://chinazzjx.com/d/files/6999127231.pdfIn PDF document text
    • https://infravoip.com/wp-content/plugins/super-forms/uploads/php/files/6e1a3baf08235c559e705dde5e7efd3c/44235062380.pdfIn PDF document text
    • http://househouse.it/userfiles/files/35398628941.pdfIn PDF document text
    • https://mashtalkandil.com/userfiles/file/65882637473.pdfIn PDF document text
    • http://jongauger.com/userfiles/file/24428723474.pdfIn PDF document text
    • http://bdsps.org/slbdavbatala/userfiles/file/68787967269.pdfIn PDF document text
    • http://nadiadsa.org/userfiles/file/winekoxubifidevefazolaw.pdfIn PDF document text
    • http://80tner.netsociality.com/upload/files/dobemoxukirikopuwa.pdfIn PDF document text
    • http://scard.vn/app/webroot/uploads/files/xuzawiguwabovuremedasub.pdfIn PDF document text
    • https://feriaesotericadeatocha.com/wp-content/plugins/formcraft/file-upload/server/content/files/161382f721208a---77413538961.pdfIn PDF document text
    • http://www.amedna.com/userfiles/files/56988859390.pdfIn PDF document text
    • https://5ky13lu3-1251.com/contents/files/nuguxalirukesusurema.pdfIn PDF document text
    • https://hgindustrial.eu/userfiles/files/nifexutululogosukesigosa.pdfIn PDF document text
    • http://alpes-de-haute-provence.proximeo.com/ckfinder/userfiles/files/22876217261.pdfIn PDF document text
    • http://chinajnbt.com/images/upload/File/tibosilewuwurek.pdfIn PDF document text
    • http://edumedcare.pl/upload/files/23343441553.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_off0000b527.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB527 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cd39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD39 15532 bytes
SHA-256: c88dff32453783d150ca28c600a76a78e39aceeeeb715d706f3ba66a4ea8c226
font_02_sfnt_off0000f4fe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4FE 10560 bytes
SHA-256: 7858809420bd588e7dac41072919aa8f51ed74d24c0958b7352f507ba890bb7e

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