Malicious PDF — malware analysis report

Static analysis result for SHA-256 d25a828f883f670a…

MALICIOUS

PDF

77.7 KB Created: 2021-09-22 11:56:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 094c832b10414f8be1e7e37541571deb SHA-1: 1dc6b5a2a2e944f7ee829d0d49a098dd2c017478 SHA-256: d25a828f883f670a0fa94615c6368e26c24a3dfb849440989a030e567da2f752
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with multiple URLs pointing to potentially compromised or disposable hosting. The document body, though heavily obfuscated, suggests it was generated by wkhtmltopdf, a tool often used to create PDF documents from web content, reinforcing the link farm hypothesis. No scripts were extracted, but the overall structure and URL analysis point towards a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://ketchas.ru/uplcv?utm_term=appaddict+for+android PDF link annotation
    • http://yoshitomo-kokubunji.com/jcfiles/file/66497124184.pdfIn PDF document text
    • http://xn----7sbbbizu2bxaod.xn--p1ai/userfiles/file/mufawevovage.pdfIn PDF document text
    • https://parlagame.net/calisma2/files/uploads/97521584953.pdfIn PDF document text
    • http://www.rec39.ru/wp-content/plugins/super-forms/uploads/php/files/141b39cb337f29e4162b94ab73dab1f9/61010040364.pdfIn PDF document text
    • http://edituj.cz/res/file/47400449076.pdfIn PDF document text
    • https://zivotzaokny.eu/res/file/vizesetekakila.pdfIn PDF document text
    • http://www.travelwithtaangoo.com/img/file/vegezosavidab.pdfIn PDF document text
    • https://xn--80adj7cxa.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/3c71688651b8337fe686e4c8c537eeab/ruvuvesijum.pdfIn PDF document text
    • https://www.educazionesessuale-scuola.ch/ck/ckfinder/userfiles/files/63891497691.pdfIn PDF document text
    • https://etcbt.com/userfiles/file/goxusidiziwisifugol.pdfIn PDF document text
    • http://seoaudytor.pl/userfiles/file/2170009577.pdfIn PDF document text
    • http://staceyasp.com/UserFiles/file/92381958817.pdfIn PDF document text
    • https://truckforceone.com/upload/editor/file/68914964029.pdfIn PDF document text
    • http://alituncer.com/userfiles/file/69769990766.pdfIn PDF document text
    • http://indianmailbox.com/assets/images/userfiles/files/refatiwonakiri.pdfIn PDF document text
    • http://uniradioweb.info/userfiles/files/ruvemabupexoritapute.pdfIn PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614827152a9d2---jesom.pdfIn PDF document text
    • http://radio-salsa.com/php/rs/filesupload/file/letevazobalozewafenej.pdfIn PDF document text
    • http://waypl.pl/upload/File/zimeret.pdfIn PDF document text
    • http://escritacontabilidade.net/fotos/news/file/kokebodevovefafeza.pdfIn PDF document text
    • https://assurancemauricie.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140531ab1ec5---8406606476.pdfIn PDF document text
    • https://cfi-registration.org/buzzboxgift/img/userfiles/files/radinowepufaruvitexabopir.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_off0000cf13.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF13 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e72a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE72A 10248 bytes
SHA-256: a95ef0bdc61a68fac8cdaa1b0acca9652786198c333063a7242674beaa88fbf2
font_02_sfnt_off0000fe45.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE45 16864 bytes
SHA-256: 2f21ca56686a5e332786908139fb754062cc9ef5c5a72b2becbf8236649d4631

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