Malicious PDF — malware analysis report

Static analysis result for SHA-256 5bb11b55d58733a9…

MALICIOUS

PDF

83.5 KB Created: 2021-09-03 14:43:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 0c253d2520a2d03526d9e248f1ec1577 SHA-1: 7b65a041764f30f2d7db8831c3eac251ff9668fa SHA-256: 5bb11b55d58733a9380021cfc154e543eb075fbfe1d4628c5b3159933ba9ef5d
156 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm pointing to compromised WordPress upload storage. The PDF contains numerous URLs, many of which are hosted on compromised sites, suggesting a phishing or malware distribution campaign. The primary attack pattern involves directing users to external, potentially malicious, content via embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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 https://www.sahabatkeluargahomecare.com/wp-content/plugins/formcraft/file-upload/server/content/files/160861b62891aa---gejuxororiburugununutupa.pdf
    • http://nutronicltd.com/userfiles/file/81954494862.pdf
    • http://harveyfamily4016.com/clients/5/51/51a16c7d09a65bdad6d3cd8ef7da6b4e/File/funamexorowigowodowu.pdf
    • http://yatros.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160abf729d015d---32750361819.pdf
    • http://machinegroup.ru/img/outer/files/lebopewuneka.pdf
    • https://ehotelgateway.com/bot/ckfinder/uf/files/rimubilaviwiwigenurol.pdf
    • http://www.magicapro.it/wp-content/plugins/formcraft/file-upload/server/content/files/161258e75bfdc5---midudurekaxe.pdf
    • http://structurecreative.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e311d7191f1---37393614061.pdf
    • http://krindustria.com.br/site/wp-content/plugins/formcraft/file-upload/server/content/files/160960ecb2770b---wevetomotunizipodupunu.pdf
    • http://mastervin.ru/files/file/82989390808.pdf
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/a9686c27cd852d4844ca98e7c393c7a6/faboletenomozoje.pdf
    • https://plentis.eu/ckfinder/userfiles/files/vegojotujetilan.pdf
    • https://inchirieriavioane.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16089a9fd27c7b---dawudagedakebira.pdf
    • https://thietbivesinhanhhuy.com/asset/files/27040246624.pdf
    • http://mauchlineware.com/html/chapelstreet/web/userfiles/files/5187427409.pdf
    • https://cristiandellavedova.com/wp-content/plugins/super-forms/uploads/php/files/9nk65ei9886a7igdt51lk99ag3/44403576076.pdf
    • http://ipmarketing.net/userfiles/file/15889968066.pdf
    • https://finestblogger.de/wp-content/plugins/super-forms/uploads/php/files/errlq48lfu44v2bk4eoovkhq4e/sipodadawepevogewitosizoz.pdf
    • https://people11people.gr/uploads/File/gevufam.pdf
    • https://fobiy.net/wp-content/plugins/super-forms/uploads/php/files/48dcc294e6eef18d968606f7eb940256/56364865764.pdf
    • https://freedomhypnosisnyc.com/wp-content/plugins/super-forms/uploads/php/files/ac4e1ca5ede71094b7f6ea939ca11417/90095551307.pdf
    • http://sportingclubalbinia.eu/userfiles/files/tuvaposabukuzivagukezepu.pdf
    • http://dralituncer.com/userfiles/file/36930570810.pdf
    • http://klick-tipp.info/ckfinder/userfiles/publics/files/59168683678.pdf
    • http://blog.crowdly.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d39a51156a---62190120055.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=bioavailability+of+curcumin+problems+and+promises+pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e01f.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE01F 16792 bytes
font_01_sfnt_off0000f831.bin
fc94561a345d04a898b349760f396d6a5dbb914d2868038e9da86df505158c44
pdf-font-stream PDF embedded font (sfnt) at offset 0xF831 17624 bytes
font_02_sfnt_off0001260a.bin
2d89b1522bb9fd04fe90b894b120e752d204345bc713d4d7a3a96329ce0d9193
pdf-font-stream PDF embedded font (sfnt) at offset 0x1260A 11252 bytes