Malicious PDF — malware analysis report

Static analysis result for SHA-256 dc8db44fb6ed4fe6…

MALICIOUS

PDF

71.5 KB Created: 2021-10-01 06:09:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 64ed3a5c1549cf9f5208ad6223052939 SHA-1: 8a17a1bec2aefd71fe938959b6ffa7c84fb01934 SHA-256: dc8db44fb6ed4fe64306f99f2383ff1171abdf4bb7ef7a319c6aa5187b6d995f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to potentially compromised websites, including one hosted on a WordPress upload storage. The embedded URLs and the overall structure suggest a phishing attempt disguised as an Android system update to lure victims.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

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 http://hotel-gerard-dalsace.com/upload/document/98600043004.pdf In PDF document text
    • https://tatvan.in/userfiles/file/jidef.pdfIn PDF document text
    • https://barrierball.cl/ckfinder/userfiles/files/lupomumini.pdfIn PDF document text
    • http://tythb.com/uploadfile/files/zajiji.pdfIn PDF document text
    • https://thriveelearning.com/wp-content/plugins/super-forms/uploads/php/files/76ab0e1e3f62119078e4a41a5b09bb30/vazoxezatamaba.pdfIn PDF document text
    • https://www.ibyservice.com/wp-content/plugins/super-forms/uploads/php/files/91bffafd7ed626012b1ad8b7c302998a/92203171300.pdfIn PDF document text
    • http://brmxn.com/userfiles/file/20210924221347_grjiu5.pdfIn PDF document text
    • https://maintogelonline.info/contents/files/23026319215.pdfIn PDF document text
    • http://pointerboards.com/uploads/admin/files/51338494341.pdfIn PDF document text
    • https://divetechmarine.com/contents/files/zuxevikigopenirizabesedo.pdfIn PDF document text
    • http://hotelpenza58.ru/ckfinder/userfiles/files/56815945940.pdfIn PDF document text
    • https://wcdt.co.th/wp-content/plugins/super-forms/uploads/php/files/uosgg8t3ts3f4qkakmgd6nlfvq/40957290921.pdfIn PDF document text
    • https://jancsoalapitvany.hu/ckfinder/userfiles/files/50787927130.pdfIn PDF document text
    • https://protrialse.eu/files/files/pofazolixalomin.pdfIn PDF document text
    • http://boras-sjuharad.boj.se/uploads/userfiles/files/nivimatidupekonugut.pdfIn PDF document text
    • https://www.esicm-old.org/admin/lib/ckfinder/userfiles/files/gibexep.pdfIn PDF document text
    • https://associazionedynamica.it/uploads/file/42192830974.pdfIn PDF document text
    • http://imcborivali.org/userfiles/file/33039956575.pdfIn PDF document text
    • https://www.bakkersvlaanderen.be/resources/plugins/ckfinder/userfiles/0/files/31468684346.pdfIn PDF document text
    • http://image.dlib.vn/libedu/news/bvu/20210916/file/gukegebebowenibamej.pdfIn PDF document text
    • http://gzcaifeilai.com/ckfinder/userfiles/files/202109291656485729.pdfIn PDF document text
    • https://amatnieks.lv/pictures/image/35842720023.pdfIn PDF document text
    • http://administratieindex.nl/images/uploads/sulefevepobadafopijafamo.pdfIn PDF document text
    • http://xn----7sbbbizu2bxaod.xn--p1ai/userfiles/file/90604653216.pdfIn PDF document text
    • http://ingegneriarossi.it/userfiles/files/6248659325.pdfIn PDF document text
    • http://asupuro.com/user_data/image/file/12079707723.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=android+system+update+10PDF 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_off0000b5d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB5D2 15916 bytes
SHA-256: 45c7cd983dc8b7ccb1fa216ce6facb27e9ab98b7dfbeda1584680dcc2bc19503
font_01_sfnt_off0000dee2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEE2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f6f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6F9 10876 bytes
SHA-256: 9f0bae5aa7f1b44b62f3c642a0be53850ec918f337818bcd7aa0ec7ae7c10f5a