Malicious PDF — malware analysis report

Static analysis result for SHA-256 a903d79dfbe117b3…

MALICIOUS

PDF

81.6 KB Created: 2021-09-01 19:20:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 3eb91cba3b039e6c1185c7a1c8a94f4b SHA-1: 01aa231d732b396a255b8a63ebf8bfc5e5ca93d2 SHA-256: a903d79dfbe117b3b7fd4afabc912996f3b799977264fa04231f4c929a50e451
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a link farm pointing to multiple URLs hosted on compromised WordPress sites, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or delivering a secondary payload. No scripts were extracted, but the structure and URL targets are indicative of a malicious document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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://study-go.info/wp-content/plugins/super-forms/uploads/php/files/f6aba48944a61b8672f750320524519e/83221520551.pdf In PDF document text
    • http://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609a099087fdf---78759439838.pdfIn PDF document text
    • http://cooper1972.com/clients/b/b4/b451ebb09e7e0345645526f893d9a49e/File/41310850874.pdfIn PDF document text
    • https://realwebguys.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f707ad9db1---sakolosalavogowawep.pdfIn PDF document text
    • http://pulsrmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b888e64deda---59049366868.pdfIn PDF document text
    • http://wrhs1967.org/clients/6/61/617565fc8afb9cc6d18abf932d248b7a/File/11383462132.pdfIn PDF document text
    • http://www.magicapro.it/wp-content/plugins/formcraft/file-upload/server/content/files/160c4b6a27d978---sizatafegefova.pdfIn PDF document text
    • http://www.consorcio.edu.pe/wp-content/plugins/formcraft/file-upload/server/content/files/160bad11e19053---77400131467.pdfIn PDF document text
    • http://bainihu.com/upfiles/editor/files/55190102409.pdfIn PDF document text
    • http://quadocdao.vn/uploads/files/jiludujunosorenu.pdfIn PDF document text
    • http://mynigaoe.com/upload/file/20210629112620.pdfIn PDF document text
    • https://xn--faades-mtal-n9a6a.ch/ckfinder/userfiles/files/wozono.pdfIn PDF document text
    • http://barnesfamilyre-union.com/clients/52050/File/memusorobozon.pdfIn PDF document text
    • http://nhsclassof77.com/clients/c/ca/caa0b9827732345dad94809623212052/File/60071762660.pdfIn PDF document text
    • http://qqsbg.net/uploads/file/86079343674.pdfIn PDF document text
    • https://nazrabilisim.com/calisma2/files/uploads/larepabe.pdfIn PDF document text
    • http://queuemanagementsystems.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c58664cb8e8---vadunikovowuv.pdfIn PDF document text
    • https://advancedbusiness.co/wp-content/plugins/super-forms/uploads/php/files/1d43f60d10f388d2103d661231a84e00/porabuzolufavupenimu.pdfIn PDF document text
    • http://thunderstar.cn/userfiles/file/20210619162507512617419.pdfIn PDF document text
    • http://amtusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bbbbc8082e1---tujakilevajonavipen.pdfIn PDF document text
    • https://www.hintonassociates.com/wp-content/plugins/super-forms/uploads/php/files/f29467d9a0fab408e9b357d075f0153e/22243184051.pdfIn PDF document text
    • http://www.risingstars.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16082edea27ee8---61857027510.pdfIn PDF document text
    • http://worldtile.net/jangheung/userfiles/file/16024494584.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=asset+formula+in+accountingPDF 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://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_off0000d9e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9E0 17916 bytes
SHA-256: aa6b911d4dbf17db9560cb0cd783bfeed0a28d0b4f892ebbe391012c2d281611
font_01_sfnt_off00010844.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10844 10760 bytes
SHA-256: d0d33113ccb703fe50200533fafc3c8a1948ae226ae24a8759ad78ed5b91e2d4
font_02_sfnt_off0001210e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1210E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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