Malicious PDF — malware analysis report

Static analysis result for SHA-256 99c008d7391a353b…

MALICIOUS

PDF

86.1 KB Created: 2021-07-24 05:30:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-29
MD5: d49ea7570c849053e5066c7c7f2dd8c5 SHA-1: 1ade3925f9eeb0b9153e636a90590912d9726983 SHA-256: 99c008d7391a353b638f57e728700806d1c51ff615dfb81f70d87bce7ade2b36
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a link farm with numerous external URIs, many pointing to compromised WordPress upload directories. The ML classifier strongly flagged this PDF as malicious. The document body is heavily obfuscated and unreadable, providing no direct clues to its intent beyond what the heuristics indicate.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9970

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://semagro-msw.ru/pics/images/file/miketizoguvemogajawiw.pdf In PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609490d63536a---topuseju.pdfIn PDF document text
    • https://bloomeng.com/uploads/xukadepakonoratafix.pdfIn PDF document text
    • https://www.sudburyhighspeedinternet.ca/wp-content/plugins/super-forms/uploads/php/files/eee4ad51eee854c29c6ab60d1cb88b1b/16877198060.pdfIn PDF document text
    • https://www.a2zmedical.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16085f75c0efae---96415023407.pdfIn PDF document text
    • http://ahkjt.com/upfile/file/kexulizakatuwaridimojotak.pdfIn PDF document text
    • http://alternativefitness.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607df49b0ebf8---18007891168.pdfIn PDF document text
    • https://astoriareiki.com/wp-content/plugins/super-forms/uploads/php/files/a4ee0b0d204bedc9026a61742094f891/13049016049.pdfIn PDF document text
    • https://www.saltriot.com/wp-content/plugins/super-forms/uploads/php/files/07930a068171611a952c55a099671fa9/zevabagavunobasibapowe.pdfIn PDF document text
    • http://villaturri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160811b1dae612---sujowi.pdfIn PDF document text
    • http://dok-vo.ru/userfiles/file/gugevegejotetanodowutakav.pdfIn PDF document text
    • http://www.chinahkcarplate.com/wp-content/plugins/formcraft/file-upload/server/content/files/160844b918aaeb---54132047219.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/160ba21166d17d---kugixelenip.pdfIn PDF document text
    • https://ecoinkworld.com/wp-content/plugins/super-forms/uploads/php/files/10d0bdd29c16fa2fdc3e6cdffd38541e/bakivoxefawe.pdfIn PDF document text
    • http://sakirnoopo.ru/wp-content/plugins/super-forms/uploads/php/files/cb1ce313b9d2ffc0c419caf6797a15ad/zefadibizetavurefogoz.pdfIn PDF document text
    • http://baihsad.com/userfiles/files/20210708_141021.pdfIn PDF document text
    • http://hrzservices.com/uploadfiles/file/xaroz.pdfIn PDF document text
    • http://www.mtpartnersfl.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c36f8f9a1a1---gubulute.pdfIn PDF document text
    • https://tkquiz.com/userfiles/file/kuzewes.pdfIn PDF document text
    • http://reszke.pl/fckeditor/editor/filemanager/connectors/php/file/15196288017.pdfIn PDF document text
    • http://home-delighted.com/user_img/files/kirirorevejozudimorobela.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=asphalt+9+highly+compressed+apk+dataPDF 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_off0000ebac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBAC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000103be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103BE 17220 bytes
SHA-256: 3eeaed11419b0f890583f4c66470b9256b35d0c6b82e3c3b2aca14bd3b090923
font_02_sfnt_off000130e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x130E0 11212 bytes
SHA-256: 7fdf2dbd6a9888c0992c9762ff0ae86141808bba2a06f355b3062d1e1ef1b4d3