Malicious PDF — malware analysis report

Static analysis result for SHA-256 87ca8485474d608a…

MALICIOUS

PDF

74.1 KB Created: 2021-06-18 00:17:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-12
MD5: bcdae09eb2321b444eb2f3bc9c60274b SHA-1: 4db3736d6e1dbe80c50f0b6b3473a4c965c05a96 SHA-256: 87ca8485474d608a91764de8cb769fe7f56b85274f2b5989955b54efbcdb52ac
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised CMS upload storage, indicating a link farm designed to distribute malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and contains metadata from wkhtmltopdf, but the primary malicious activity is the distribution of links to other potentially harmful PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://sportli.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/1608828c2d1b40---955750373.pdf In PDF document text
    • http://bestforfishing.com/wp-content/plugins/super-forms/uploads/php/files/cea0b9d826212b035c6bd0536dc0bf5e/sajilitogafi.pdfIn PDF document text
    • https://cristiandellavedova.com/wp-content/plugins/super-forms/uploads/php/files/tp3pde70d9p1b7dc2qcl6p8if3/fufopufubizilebivopulezir.pdfIn PDF document text
    • http://svs-pm.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608a964a91c3d---xewekamuvuwiwenonigiwapum.pdfIn PDF document text
    • https://oneremote.ru/wp-content/plugins/super-forms/uploads/php/files/e3c902dc5f4c84114ef1af7f7934caac/47953063463.pdfIn PDF document text
    • http://saamfactory.com/wp-content/plugins/super-forms/uploads/php/files/4edfc9a5703675ae68086b47828cb5c4/16804336267.pdfIn PDF document text
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1607e62ea35031---tonetekimuxodidab.pdfIn PDF document text
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160c7ab6f2101c---vutagajupobige.pdfIn PDF document text
    • https://petroblend.com/wp-content/plugins/formcraft/file-upload/server/content/files/160baf29e17f9e---23699307065.pdfIn PDF document text
    • http://www.rec39.ru/wp-content/plugins/super-forms/uploads/php/files/db283cc19bc60242ae933f56a70fefde/35323123187.pdfIn PDF document text
    • https://tlpnw.com/wp-content/plugins/super-forms/uploads/php/files/f6706db05bc4f08b3cc6d15fb60c515b/66292665523.pdfIn PDF document text
    • http://cgt-fo-csc.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16094b063b1708---55451526545.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2d1e666a29---20183155372.pdfIn PDF document text
    • https://2greenchicks.com/wp-content/plugins/super-forms/uploads/php/files/3a1c0ff4cf898dd67a2ceebde2919f40/wekuxupunizolifuzil.pdfIn PDF document text
    • https://evenimentecastel.ro/wp-content/plugins/super-forms/uploads/php/files/ffn74mcv4sa7ua3853ckm5tnad/98222411305.pdfIn PDF document text
    • http://aep-tc.com/cache/fck_files/file/vugikadepekijatepipobira.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=good+free+video+editing+appsPDF link annotation
    • 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e61a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE61A 5268 bytes
SHA-256: bda27bbd90a0592219c15ed4d7048ac7bb703f2aff11a8595ba2581eb0519b4a
font_01_sfnt_off0000f827.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF827 10528 bytes
SHA-256: aa2562bef94b3fed645b4d2aab33ee4f08dee939dd7e2df61dc6f14c8a38fff0