Malicious PDF — malware analysis report

Static analysis result for SHA-256 a91eb1da0aa43760…

MALICIOUS

PDF

81.4 KB Created: 2021-06-25 16:57:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 4326ca0bf4c07c3f6f85c906bbd9f1de SHA-1: 48b713ca7ec5af0c16bf72af7f7acfe4b1a10181 SHA-256: a91eb1da0aa4376057744adddc92bde9de81a3c1e41435e783b0ec48b3b422af
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF that exhibits characteristics of a link farm, with numerous URLs pointing to compromised WordPress sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and embedded URLs suggest it's designed to lure users to external, potentially malicious, resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 http://willtorock.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d95503640c---tigoduposowefudamu.pdf In PDF document text
    • https://okud-istra.hr/userfiles/file/92859404060.pdfIn PDF document text
    • https://www.toptalentusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b584084761---tozuxo.pdfIn PDF document text
    • https://www.mii.net/wp-content/plugins/super-forms/uploads/php/files/9f651d1dba9d6e98887e5086c2c5477c/xometowebomopinefunivu.pdfIn PDF document text
    • http://kindervakantieweekdeurne.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160cd765dd35e2---tejakokolobaxikim.pdfIn PDF document text
    • https://audreyheselmans.com/_files/file/buredijirukokigitazug.pdfIn PDF document text
    • https://comodee.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082fc28812b7---dajanote.pdfIn PDF document text
    • https://finestblogger.de/wp-content/plugins/super-forms/uploads/php/files/em3is6es2oo4f3un054copr1kr/41677885952.pdfIn PDF document text
    • http://daotaonhaccong.com/uploads/userfiles/file/71453667136.pdfIn PDF document text
    • http://www.moteco.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160964be066780---59983091867.pdfIn PDF document text
    • http://leap-egypt.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609868270cd48---xuwexazenifewulule.pdfIn PDF document text
    • https://my-natural-style.net/upload/files/metipilapovejo.pdfIn PDF document text
    • https://goactive.hu/wp-content/plugins/super-forms/uploads/php/files/511a5b6217a5c9597f0d55b067d41067/pogatetobux.pdfIn PDF document text
    • http://www.lifestaralberta.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098b0dd46841---46475656300.pdfIn PDF document text
    • http://sacoorhealth.pt/site/upload/file/pesunanis.pdfIn PDF document text
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608dd5b679081---69708503720.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=ventricular+systolic+functionPDF 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_off0000deb4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEB4 10512 bytes
SHA-256: c7d017435db08300a4e2f454891e5b74fcdbdf4be3f346d5dba216425861b55a
font_01_sfnt_off0000f6d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6D0 16228 bytes
SHA-256: 177caee4544e405993830b0939ac801f96bbb199c0f7d08dffe8a41ec4f6f6f7
font_02_sfnt_off00012110.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12110 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1