Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3cef74869e37d90…

MALICIOUS

PDF

72.0 KB Created: 2021-09-09 09:49:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 70f9ff442f5d1f89f95688b00f01ae2b SHA-1: 0256cd6441c2862e83eda507440863bb34767ecb SHA-256: a3cef74869e37d90826dd685526520204e2b9c7f38755d8539ec79f8be2c07e7
96 Risk Score

Malware Insights

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

The PDF contains a large number of links, many pointing to domains identified as potentially compromised or disposable hosting. The ML classifier strongly indicated maliciousness, and the structure suggests a link farm designed to redirect users to external sites. No scripts were extracted from this sample, limiting the analysis of direct execution capabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9902

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 http://vetcasatenovo.it/userfiles/files/xolowokikimerolobizo.pdf In PDF document text
    • https://autosofortkauf.ch/wp-content/plugins/super-forms/uploads/php/files/oj881e82piequelsi4mfbpt8m0/kosazekejakedujotowixova.pdfIn PDF document text
    • http://etalentlink.com/uploadfile/file///2021090712504021.pdfIn PDF document text
    • http://ifaistos.reality.gr/~triantaf/images/file/20875771333.pdfIn PDF document text
    • http://pathtojanna.com/userfiles/files/32626449395.pdfIn PDF document text
    • http://klccpa.com/userfiles/file/vuzasilibatomevozire.pdfIn PDF document text
    • http://www.anaja-inter.org/public/file/34715996426.pdfIn PDF document text
    • http://chaputlawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/pujapijisulajenaxa.pdfIn PDF document text
    • https://palet-school.com/files/files/wowanofebudeg.pdfIn PDF document text
    • http://ecohort.com/userfiles/files/14229877158.pdfIn PDF document text
    • https://drbumbnursinghome.in/ckfinder/userfiles/files/wujugivasagadukelapakotop.pdfIn PDF document text
    • https://www.syria-report.com/sites/all/libraries/ckfinder/userfiles/files/42555961318.pdfIn PDF document text
    • http://www.cerel.eu/images/wyswig_images/file/xanisolixuwovatubotit.pdfIn PDF document text
    • http://www.predia.cz/userfiles/file/57571901724.pdfIn PDF document text
    • http://grapes4u.ca/sites/all/sites/grapes4u.ca/files/movojakinotukimibalap.pdfIn PDF document text
    • https://honghow.com/ckfinder/userfiles/files/54620556096.pdfIn PDF document text
    • https://girisimhaber.com/uploads/file/12760457824.pdfIn PDF document text
    • http://manegedebuitenwijck.nl/uploads/file/47491033113.pdfIn PDF document text
    • http://www.1atlanticfunding.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613002c00d2bc---sozusovetugodexog.pdfIn PDF document text
    • https://penzion-pod-rozhlednou.cz/img/file/5962380066.pdfIn PDF document text
    • http://assushop.com/userfiles/assushop.com/file/niwibifolewej.pdfIn PDF document text
    • http://studiomuraca.eu/userfiles/files/kewogujatewizeg.pdfIn PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/53b40936a66bfcf0182f12ca64639a0d/23791823203.pdfIn PDF document text
    • http://thayloilocnuoctaihanoi.net/upload/files/3098847209.pdfIn PDF document text
    • https://www.syah.org/wp-content/plugins/super-forms/uploads/php/files/75ef0a650b6acc34c14f0060c787fc32/bajegudusokofemomux.pdfIn PDF document text
    • https://mk-promotions.com/ckfinder/userfiles/files/gezadosawiwimefomuvegenad.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=option+menu+android+examplePDF 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_off0000b85c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB85C 10612 bytes
SHA-256: dbf822d4ad615880987d024e65270563c834fc2bb761c60716f8f8f8700c933f
font_01_sfnt_off0000d097.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD097 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e8a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8A9 16352 bytes
SHA-256: e9ba3af1ddccc9e6288009c8812427d68bf6dab6f6e03bbb89fbb102dd780ef0