Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3c5a36397c1578a…

MALICIOUS

PDF

86.5 KB Created: 2021-09-04 14:23:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 9718085f8a5d5d1098f0096f400fcdef SHA-1: 4a64aec9d80eff7506daa1114d28366bc6bb0bc5 SHA-256: a3c5a36397c1578ad2e601ecd08d3d8589af108885c5227c1279807026b636fd
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links pointing to compromised WordPress sites, specifically within the 'formcraft' and 'super-forms' plugins, which are often abused for hosting malicious files. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is unreadable, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://www.msolartop.cz/wp-content/plugins/formcraft/file-upload/server/content/files/160a168c45d3eb---18735529463.pdf In PDF document text
    • http://mesotects.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607573653e7ca---nizedofonokibusivufi.pdfIn PDF document text
    • http://bezpieczna-strefa.pl/wp-content/plugins/super-forms/uploads/php/files/5fc53d0f670efe46795fbaa8981ac069/70181908509.pdfIn PDF document text
    • http://huichem.com/ckfinder/userfiles/files/rosaxoketefunaz.pdfIn PDF document text
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d0e8d494ae---18263383886.pdfIn PDF document text
    • https://thejinglelab.com/wp-content/plugins/super-forms/uploads/php/files/rsjpntul78pmgpdheecg0iqcfc/lugesoxabipikudi.pdfIn PDF document text
    • https://sancarspune.com/wp-content/plugins/super-forms/uploads/php/files/a3d710984f69a3a28d29088f932a66b0/58371521205.pdfIn PDF document text
    • https://www.dynasil.com/wp-content/plugins/super-forms/uploads/php/files/1eac6830e2b5013133eb8ed15ce91dce/68048228219.pdfIn PDF document text
    • https://vakukh.ru/wp-content/plugins/super-forms/uploads/php/files/01cf94cb096bc5d763c35343a6abdaad/jopupomugo.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/s4n1j472lg18g2aabg2cc1ekt6/dimofawipijobo.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/16087585ccdabe---19018171271.pdfIn PDF document text
    • https://sankohomestay.com/userfiles/files/27857223164.pdfIn PDF document text
    • https://www.colegiodesafio.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/1607e9b0b40d76---31919196903.pdfIn PDF document text
    • https://matratva.in/userfiles/file/pepakabikowopuditomukobis.pdfIn PDF document text
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160836214bc1d2---33402591956.pdfIn PDF document text
    • https://traiteur-troyes-mariage-buffet-aube-10.blaisot-traiteur.fr/ckfinder/userfiles/files/tefura.pdfIn PDF document text
    • https://transcendenceit.com/wp-content/plugins/super-forms/uploads/php/files/e7a4d5541cd21b464573cf010cf18c59/37062525663.pdfIn PDF document text
    • http://elmbbq.com/uploads/files/71000054255.pdfIn PDF document text
    • http://briarcliff68.com/clients/71184/File/48919405319.pdfIn PDF document text
    • https://www.andyselfstorage.co.uk/wp-content/plugins/super-forms/uploads/php/files/vmoafiprtp1pjb17mgc3ds1od9/vufifubovom.pdfIn PDF document text
    • http://worldprint.su/userfiles/file/bukatadilazodowofosu.pdfIn PDF document text
    • https://enville.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088b404454e4---sunupuda.pdfIn PDF document text
    • https://www.ayersworthglen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e83c8684a6a---virofapu.pdfIn PDF document text
    • https://pabausa.org/wp-content/plugins/formcraft/file-upload/server/content/files/16105189eb4f0b---fubakodezixejuzit.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/160aa3878e5ad8---98374952408.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=overdryve+7+user+manualPDF 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_off0000ed0c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED0C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001051e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1051E 17992 bytes
SHA-256: 752ccb382508a3fef17dacedd2bb4d447b5ad158e57dc6ba01647045491998a2
font_02_sfnt_off00013411.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13411 10452 bytes
SHA-256: 16dd7fb5493e22c5f76ee8a9cc478709aa16f7700ec77a2d8eece3b10e1bf062

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