Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8ebc356da3a0df0…

MALICIOUS

PDF

78.2 KB Created: 2021-09-05 01:27:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: dff9b4bcf06d2fe01f3cff96ac804958 SHA-1: 93c7c2293a3ac1f93cb6d0e30245559de8aaf9ae SHA-256: a8ebc356da3a0df0d42ef47b9caa6ea821afd5beb76f2c7c5cfecec528dc485c
96 Risk Score

Malware Insights

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

The ML classifier strongly indicated maliciousness, and heuristics identified the PDF as a link farm pointing to numerous external URLs, many hosted on compromised CMS upload directories or disposable domains. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 5

  • 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://festival.bg/fckeditorfiles/file/37472192958.pdf In PDF document text
    • https://noble-worldwide.com/wp-content/plugins/super-forms/uploads/php/files/74161617bd29e7f534e8ba25dc0db3e6/zizolafuvovoru.pdfIn PDF document text
    • https://concertwristband.com/resimler/files/89875522241.pdfIn PDF document text
    • https://kicksomeglass.com/wp-content/plugins/super-forms/uploads/php/files/9bf09c08c1e4aceeea7dc00e869ed805/14098692575.pdfIn PDF document text
    • http://mea-travel.pl/userfiles/file/6751885643.pdfIn PDF document text
    • https://monacollection.ua/wp-content/plugins/super-forms/uploads/php/files/c5c2f19cc3f7bfbb3fd72b12a90da713/47687072990.pdfIn PDF document text
    • http://botanicgardenscafe.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608db9a47e704---46733687346.pdfIn PDF document text
    • http://ahcxdq.com/uploads/file/231147557288.pdfIn PDF document text
    • https://www.infrascale.com/wp-content/plugins/super-forms/uploads/php/files/286891d2dc2264522cfb62f7d8884574/xenireduvidivere.pdfIn PDF document text
    • https://refundsrefunds.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f155fc303cd---todepaxebinafusalisexoxok.pdfIn PDF document text
    • http://bioscipublisher.com/files/upfiles/file/zilafipilemujiwatugop.pdfIn PDF document text
    • https://sgdivorcelawyers.com/wp-content/plugins/super-forms/uploads/php/files/42355fa46486bff64eaa44c6140a2171/58903355801.pdfIn PDF document text
    • http://srub-servis.ru/userfiles/file/fiwewepoputixomilosa.pdfIn PDF document text
    • http://www.polni.si/Images/files/pafamuma.pdfIn PDF document text
    • http://ipjanah.ir/wp-content/plugins/super-forms/uploads/php/files/oq982hpe435s6806h9fsthpg12/riwodusifufudo.pdfIn PDF document text
    • http://pmdrecycling.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cc36e47107---85899324044.pdfIn PDF document text
    • http://naosgym.com/userfiles/files/86491720326.pdfIn PDF document text
    • http://stkvn.ru/wp-content/plugins/super-forms/uploads/php/files/f00f8dcfac7b676934b8472311b5624d/38576491641.pdfIn PDF document text
    • https://www.brunosistemi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cae0a94faf---70278894.pdfIn PDF document text
    • http://pokrowce-ochronne.pl/Upload/file/78390315710.pdfIn PDF document text
    • http://lookupagency.es/wp-content/plugins/formcraft/file-upload/server/content/files/160915f36549c6---xumewe.pdfIn PDF document text
    • http://cukierniabrzezinski.pl/www/artizam/fck/file/65189927308.pdfIn PDF document text
    • http://arebiatours.com/uploads/files/46822979089.pdfIn PDF document text
    • https://extremetour74.ru/wp-content/plugins/super-forms/uploads/php/files/ad6e03fe26c60312e67ff93a757c8642/vibupuwop.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=charte+des+droits+et+devoirs+du+citoyen+fran%C3%A7ais+naturalisation+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_off0000c765.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC765 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000df77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF77 18380 bytes
SHA-256: 22cafd52d048a246a10d8bfa1ab62fd25e0c962e4a16d10b30105edd30aad8ad
font_02_sfnt_off00010dd3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DD3 11224 bytes
SHA-256: ba220ec72872ea2c948694c6b678522b37da0ea28a37d1f1ba23bb5954dfc602

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