Malicious PDF — malware analysis report

Static analysis result for SHA-256 c352c41912f5e4ee…

MALICIOUS

PDF

73.3 KB Created: 2021-09-05 03:06:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 535f040c2d83d948309c2ee237dfd7f2 SHA-1: 9791d5d70d60554de99d906ffb23846743762f47 SHA-256: c352c41912f5e4ee1a41425d3b2c51c997b9d3485d32ed5588ceda7f8c69bb6b
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous URLs pointing to compromised CMS upload storage, forming a link farm designed to redirect users. The PDF structure itself does not contain readable content, suggesting its primary purpose is to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://jollytime.ru/wp-content/plugins/super-forms/uploads/php/files/cbb9796930a938f9ae3f786c29e4f0fc/33168576246.pdf In PDF document text
    • https://cullinanconstruction.com/wp-content/plugins/super-forms/uploads/php/files/7kb23rpqoo0907esmhn3p4sb4k/zanavupufit.pdfIn PDF document text
    • http://dodici12.ru/wp-content/plugins/super-forms/uploads/php/files/5r7hjf9rc2jfv8n8p9q9v1bmj7/televemolitu.pdfIn PDF document text
    • http://kadh.kr/bobod/upload/file/21657371872.pdfIn PDF document text
    • http://english-life.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1606ca3b99b320---75613934786.pdfIn PDF document text
    • https://kimtuong.vn/isc/public/files/fckupload/file/tipakunejexobugajotaxesud.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/7024655d9f8e167a621aa66823005867/ruwememuvafijageteko.pdfIn PDF document text
    • https://kvartira-zalog.ru/wp-content/plugins/super-forms/uploads/php/files/1b040de94edc83579e2958bf87c398af/faredalos.pdfIn PDF document text
    • http://sineadstone.com/userfiles/file/wamoforeli.pdfIn PDF document text
    • http://xn--80aaae7amexjfdlfdfg.xn--p1ai/files/file/padesasodinizipezuvubopiw.pdfIn PDF document text
    • http://bridgesonthepark.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608401b629653---kijifetuw.pdfIn PDF document text
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/rao237jvphg1kflv119qt32fi1/bogetesuvomevabo.pdfIn PDF document text
    • http://traditionsradio.com/wp-content/plugins/super-forms/uploads/php/files/an3kfq9emii4jp8o8p049qihl7/ditamemixoridumibisisiv.pdfIn PDF document text
    • https://fullhousetourism.com/UploadFiles/file/20210617011310189.pdfIn PDF document text
    • https://www.projectorrentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/160920d894e1f2---wagorojabutiregar.pdfIn PDF document text
    • http://18554080.com/userfiles/file/39812840887.pdfIn PDF document text
    • https://mzlpro.com/web/img/podborky/files/vupokavidalureresifufol.pdfIn PDF document text
    • http://abogadosaguilar.com/ckfinder/userfiles/files/79807002786.pdfIn PDF document text
    • https://ibeguiristain.com/userfiles/files/xagemotepo.pdfIn PDF document text
    • http://entryexpress.online/chapter_images/files/62706024973.pdfIn PDF document text
    • http://www.logomarcanet.com/userfiles/file/turinusiguvew.pdfIn PDF document text
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/160b246ce8cf19---petukaxanemetarewe.pdfIn PDF document text
    • http://ebslang.net/_UploadFile/Images/file/33897661043.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=emotional+intelligence+and+leadership+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_off0000bd52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBD52 11048 bytes
SHA-256: a312d93654f21045b5afc90763d08874d838ea98c9ff9d39dbf153abc9905b0d
font_01_sfnt_off0000d68f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD68F 16132 bytes
SHA-256: c13c39f53f12316123f18cc654e8d3d2c92f539f0800723f219f4009bf064560
font_02_sfnt_off0000ff1e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF1E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1