Malicious PDF — malware analysis report

Static analysis result for SHA-256 775587ef429d960a…

MALICIOUS

PDF

104.5 KB Created: 2021-07-13 19:59:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 4ddae37cca3f81062d7a7f16ec318927 SHA-1: 98f9790f5fc000be40fa7439b9341bb97b5a668e SHA-256: 775587ef429d960ae0d782045a83b3a2f88412c3a0274beda85c8e90f08aa88f
156 Risk Score

Malware Insights

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

The sample is a PDF identified as malicious by ClamAV and an ML classifier. It functions as a link farm, containing numerous URLs that point to other PDFs hosted on compromised websites. This suggests a phishing or malware distribution campaign, where the initial PDF serves as a lure to redirect users to malicious content. No scripts were extracted, and the document body was unreadable, but the heuristic firings strongly indicate a malicious link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9919

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://greshamgilessalon.com/wp-content/plugins/super-forms/uploads/php/files/294727517d2c123b289cea369521de33/95320029066.pdf In PDF document text
    • http://sun-green.be/ckfinder/userfiles/files/kexubanu.pdfIn PDF document text
    • http://seksdagen.nl/userfiles/file/luketipi.pdfIn PDF document text
    • https://najarshi.com/basefile/najarshicom/files/26370919644.pdfIn PDF document text
    • http://vandervalk.reviews/app/webroot/files/userfiles/files/bibikoj.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/vr058tcodbjg6pjl59drh7rj66/28764130745.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/16071ad62ad2c5---49872203615.pdfIn PDF document text
    • http://www.advancedevents.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160797ce97f38b---76298133850.pdfIn PDF document text
    • http://abwjefferson.com/uploads/files/xipaxa.pdfIn PDF document text
    • https://ktmcollege.org/public_html/userfiles/file/37618455010.pdfIn PDF document text
    • https://t4g.nasscomfoundation.org/wp-content/plugins/super-forms/uploads/php/files/ni97r24lbiecnmbtcrcvfi3525/3223054221.pdfIn PDF document text
    • https://appfacile.it/file/tenuxil.pdfIn PDF document text
    • http://biurod9.pl/public/userfiles/file/26493313443.pdfIn PDF document text
    • http://jncs.kr/page_data/file/20210705115035.pdfIn PDF document text
    • http://weberstellen.ch/userfiles/file/gibuwenapumafosaz.pdfIn PDF document text
    • http://billsky.ee/files/file/50693080626.pdfIn PDF document text
    • http://antwerp-rentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c88892335a---7221222014.pdfIn PDF document text
    • http://kartinatv.org/uploads/files/86051867955.pdfIn PDF document text
    • https://vickers-electronics.co.uk/wp-content/plugins/super-forms/uploads/php/files/b53e42edc6ad95df0cbb1bf631b62b7b/24242402545.pdfIn PDF document text
    • http://boxethai38.com/upload/file/45536156958.pdfIn PDF document text
    • http://fundraisingwebsites.com/clients/9/96/963d931f30a9d2280975e71a7f923c96/File/44788260389.pdfIn PDF document text
    • https://skvely-kup.cz/files/file/67929069342.pdfIn PDF document text
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/160c5f5b634aed---fibopegawavexova.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075b4c4a9261---jugamumoxejijesonelona.pdfIn PDF document text
    • https://eliteswimmingpoolsinc.com/wp-content/plugins/super-forms/uploads/php/files/nsu992mvap7i3t9io8mn5bgkf6/nugajozo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=if+you+not+herePDF 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_off00013777.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13777 18988 bytes
SHA-256: 1de9ad2694ee405496e1c0c9238917963543199779e608c3c44791cd480cb07f
font_01_sfnt_off000166dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x166DC 10008 bytes
SHA-256: d63d307b18ec587ffec21c621507669cfb8383d664a94be1344bc1f697fc7fbb
font_02_sfnt_off00017d09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x17D09 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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