Malicious PDF — malware analysis report

Static analysis result for SHA-256 20cfe91cf7c2e5c8…

MALICIOUS

PDF

102.5 KB Created: 2021-08-19 04:08:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: bebc17e510b633943591b452d5a350db SHA-1: 57951bbfbcf9ab9a7be977dc639397b5ae2ce9ae SHA-256: 20cfe91cf7c2e5c8cb5690235e8737fcbab77bbab2fe2db6e5d8e3eaff6c01e8
176 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal malformed streams and a link farm pointing to compromised and disposable hosting, suggesting the PDF acts as a lure to download further payloads. The presence of numerous external URIs, many hosted on compromised WordPress sites, reinforces the attack pattern of directing users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://monkey-do.net/userfiles/file/verinu.pdf In PDF document text
    • https://almudenafernandez.co/ckfinder/userfiles/Files/jumimukanufokuwamiz.pdfIn PDF document text
    • https://securitydm.rs/slicice/file/wovuzemusiwinapi.pdfIn PDF document text
    • http://www.grundys.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160c0ec4cddc37---mudagixowilo.pdfIn PDF document text
    • http://shmountaineering.co.uk/wp-content/plugins/super-forms/uploads/php/files/rfnbn6vnvl4500vib79hhdvee1/runebik.pdfIn PDF document text
    • https://malimbe.africa/wp-content/plugins/super-forms/uploads/php/files/7d2c72cbdb0f182cc68dfc508f0532f1/jolesapawugu.pdfIn PDF document text
    • http://bwc.lt/i/kusukidilejusabubasogez.pdfIn PDF document text
    • http://lawcab.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1609c082445e60---megegadejimopinigujox.pdfIn PDF document text
    • http://svx.su/ffile/file/90686005587.pdfIn PDF document text
    • https://homini.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1607d232e62e71---fovavetozerosupeduwovo.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c9756863abc---26847541899.pdfIn PDF document text
    • https://unitedcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c4469b73028---35641867293.pdfIn PDF document text
    • http://stroynerud-sm.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160b168635041b---564907494.pdfIn PDF document text
    • https://kes-stv.ru/wp-content/plugins/super-forms/uploads/php/files/052d744ba322b0ef6fb682b3f701a5b2/busabujasopinimilewolu.pdfIn PDF document text
    • http://hoondb.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082e0168f36e---82170866088.pdfIn PDF document text
    • https://lostsoulsmemorialnj.org/wp-content/plugins/super-forms/uploads/php/files/1525cfe4c811acad9e0e63a33a2b11bb/23012954659.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/30jqfnerjr4v5q81dboob104i6/23064905816.pdfIn PDF document text
    • https://agrilaui.com/userfiles/file/fawerumetigoxiduxu.pdfIn PDF document text
    • http://aberdeeneyes.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607233eb9b88a---towafefafalukusibarixivat.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c171f8734e2---marorawinokerupofe.pdfIn PDF document text
    • https://fitness-sport.it/userfiles/file/fugaxoxoboludijerar.pdfIn PDF document text
    • http://matrixuniverzum.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160c9ae762f1e1---fepenobimazudedakekamuwuf.pdfIn PDF document text
    • http://tamtamphat.com/upload/files/39515894937.pdfIn PDF document text
    • http://www.justgiveahand.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607bc4b99680d---91388051693.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=reflection+and+refraction+worksheet+4th+grade+pdfPDF 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_off00012808.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12808 11200 bytes
SHA-256: 24dfc6ae1f1a99f7dcd5e13fdff44e7e12c205fc33799dd786259420575e2952
font_01_sfnt_off00014213.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14213 18412 bytes
SHA-256: afd7c7470e56193f2ae673abdd15109299c475ccc1d85fdb087a6e4c23814bda
font_02_sfnt_off000172e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x172E7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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