Malicious PDF — malware analysis report

Static analysis result for SHA-256 f1b481b5c2e2237f…

MALICIOUS

PDF

69.6 KB Created: 2021-09-12 13:51:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 8bea1874335b45002091d96ceffc8d00 SHA-1: 6b78f3fef358313c29b446c2bbebf5934527f4ba SHA-256: f1b481b5c2e2237f68371a305f586ae576199d83d7f46e70731587ee230c2cab
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. The heuristics indicate it functions as a link farm, directing users to numerous distinct hosts, with one notable URL being http://15441707.com/data/board/file/20210912135319.pdf. This suggests the document is designed to trick users into visiting potentially harmful websites, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://15441707.com/data/board/file/20210912135319.pdf In PDF document text
    • https://bravo-hk.com/userfiles/file/gowovofimadetoj.pdfIn PDF document text
    • http://www.gpe-el.pro/ckfinder/userfiles/files/91592599290.pdfIn PDF document text
    • http://currycornersugarland.com/admin/images/file/76955602064.pdfIn PDF document text
    • https://copyjokertw.aw6.tw/uploadfile/qu4_qu106_com/files/kokufiminisovorewizomuwuv.pdfIn PDF document text
    • https://holocaustresearch.pl/nowy/photo/file/rapobatikajujukimat.pdfIn PDF document text
    • http://gearonlaw.net/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/jalavinawezir.pdfIn PDF document text
    • http://danguykhoidoanhnghiephp.vn/Upload/files/24653377724.pdfIn PDF document text
    • http://technology-mp.it/userfiles/files/69895145829.pdfIn PDF document text
    • https://webrobogo.hu/kepek/semitaxokofuwafopax.pdfIn PDF document text
    • http://dungcubepgiangtrinh.com/webroot/img/files/68621221587.pdfIn PDF document text
    • https://bestcoloringpages.com/userfiles/file/limolejo.pdfIn PDF document text
    • https://thehouseconcert.com/ckfinder/userfiles/files/momuperoveniju.pdfIn PDF document text
    • https://tempegaring.com/contents/files/73559437738.pdfIn PDF document text
    • http://graviroz.hu/ckfinder/userfiles/files/bamonuroxogiwikawumurik.pdfIn PDF document text
    • http://kartinatv.org/uploads/files/37917868111.pdfIn PDF document text
    • https://gres-k.cat/userfiles/file/tojufakuw.pdfIn PDF document text
    • https://drahmetbostanci.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139d4d8259f1---xosimugomemabodefum.pdfIn PDF document text
    • https://www.tahitotfalu.hu/ckfinder/userfiles/files/27398766214.pdfIn PDF document text
    • https://www.potravinyav21.cz/ckfinder/userfiles/files/19568187239.pdfIn PDF document text
    • http://izeninfo.net/admin/upload/files/5520619932.pdfIn PDF document text
    • https://kapefashion.com/files/files/62567969722.pdfIn PDF document text
    • http://teakdeck.pl/files/file/99900422192.pdfIn PDF document text
    • https://whiteplacard.com/UserFiles/file/wowororobevagaza.pdfIn PDF document text
    • http://www.training4thefuture.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613afb1b413e0---muloxosonebixakezezafig.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=fifa+mobile+update+apkPDF 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_off0000b45c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB45C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cc73.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC73 10596 bytes
SHA-256: 71f091e950b38968151a1cea69b14074f3551a9a9e2dac8f1d4e62bf2a7bca84
font_02_sfnt_off0000e468.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE468 14524 bytes
SHA-256: 3b2ae1b6241fe66126eeba5008de8bd0c3232fb0b1ef52573eceb2dcc32441a1