Malicious PDF — malware analysis report

Static analysis result for SHA-256 961bcb1d08efdd46…

MALICIOUS

PDF

74.5 KB Created: 2021-09-02 08:00:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 51cb4c964e5b1b15c5b052fa6d460b82 SHA-1: 7e98d7f0801393d605225fbc05a2f0a1944c71bb SHA-256: 961bcb1d08efdd46f3b182fc3be7435b0c2a688ad2c95d593121aa054e88f772
96 Risk Score

Malware Insights

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

The PDF file contains a link farm, with multiple URLs pointing to compromised CMS upload directories. The ML classifier strongly indicated maliciousness, and the structure suggests an attempt to lure users to external sites, likely for further exploitation or phishing. No scripts were extracted, limiting the analysis of direct execution vectors.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://pikewallis.no/wp-content/plugins/formcraft/file-upload/server/content/files/16076cf2694bdc---jumusixiwobanasubu.pdf In PDF document text
    • https://www.multilandtours.com/assets/ckfinder/userfiles/files/35511610310.pdfIn PDF document text
    • http://brmxn.com/userfiles/file/20210627063456_xda7d1.pdfIn PDF document text
    • https://vigiweb.cl/dinamicos/files/file/24806351730.pdfIn PDF document text
    • https://webmodels.studio/wp-content/plugins/formcraft/file-upload/server/content/files/16073d5f5c057a---52409722694.pdfIn PDF document text
    • http://sunnysolutions.it/uploads/assets/file/82113645612.pdfIn PDF document text
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a45b93e3db1---53819462052.pdfIn PDF document text
    • http://goldmustang.ru/files/files/65411008835.pdfIn PDF document text
    • https://joyfool.art/wp-content/plugins/super-forms/uploads/php/files/b48d62733efa139726a05882c57b08e1/22864225080.pdfIn PDF document text
    • https://evenimentecastel.ro/wp-content/plugins/super-forms/uploads/php/files/am8tq8cpofrlvl880uq51smagb/70849989857.pdfIn PDF document text
    • http://werder-ritter.de/UserFiles/File/kurosuwimemusufe.pdfIn PDF document text
    • http://fgosvo.ru/files/files/dodumevuba.pdfIn PDF document text
    • https://prevodi-plovdiv.com/userfiles/file/64981536644.pdfIn PDF document text
    • http://jjmcp.jp/userfiles/Image/file/tefuref.pdfIn PDF document text
    • http://anhuishangbiao.com/upload_fck/file/2021-6-1/20210601091027823775.pdfIn PDF document text
    • https://kfz-gutachter-oliver-schiller.de/wp-content/plugins/formcraft/file-upload/server/content/files/160aec2951e3c3---sedikinam.pdfIn PDF document text
    • http://www.mediagrand.hu//data/editorfile/6464526426.pdfIn PDF document text
    • http://thementalhealthadvocates.org/files/userfiles/file/29701883803.pdfIn PDF document text
    • http://www.associatedomains.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608066769c392---55145644917.pdfIn PDF document text
    • http://kliknetezde.cz/admin/obrazky/file/xibit.pdfIn PDF document text
    • https://wecareprogram.org/images/file/7710807890.pdfIn PDF document text
    • https://scriptdd.com/_file/file/83823017355.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=collective+nouns+worksheet+for+grade+3PDF 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_off0000be77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBE77 11304 bytes
SHA-256: d47ae77533805d67a214a28de0a25f2038177d24bc844c31832ce96e500ded3b
font_01_sfnt_off0000d8e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8E4 16652 bytes
SHA-256: f9b7f5a73ce6fea0a025c8d2dcf81f31485a046a596d8be524e5516bbbe14fda
font_02_sfnt_off000103bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103BB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1