Malicious PDF — malware analysis report

Static analysis result for SHA-256 81898bf8a5d6432c…

MALICIOUS

PDF

84.3 KB Created: 2021-09-11 11:48:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 1de8253eaa0ce50059f7b3a0639ac30e SHA-1: 76dff84935c427ccb0cb144530be9411a7f5c408 SHA-256: 81898bf8a5d6432ce07d759df37afb7d53993a08c93dfa82ccf176390f560889
174 Risk Score

Malware Insights

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

This PDF sample was flagged as malicious by multiple heuristics, including a high-severity PDF_RANDOM_URL_LINK and ML_NYX_PDF_MALICIOUS. It contains embedded JavaScript, which is often used to exploit PDF reader vulnerabilities or redirect users to malicious sites. The numerous external URLs, many hosted on disposable domains, suggest a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://crewmak.ru/uplcv?utm_term=android+search+app+by+name PDF link annotation
    • http://dental-forum.ru/userfiles/file/71649415799.pdfIn PDF document text
    • https://quangcaonoithatgiahung.com/admin/webroot/upload/image/files/40508204458.pdfIn PDF document text
    • http://brixtontaxi.com/survey/userfiles/files/kifaxefukapubar.pdfIn PDF document text
    • http://paulgraphics.paulsfashion.in/files/tiluxozuf.pdfIn PDF document text
    • https://childrencareandliteracysociety.org/userfiles/files/28706733349.pdfIn PDF document text
    • http://dspec-car.com/js/upload/files/rowimerizixoriju.pdfIn PDF document text
    • http://sdtrafficticketlawyer.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/45615491710.pdfIn PDF document text
    • http://twfbs.com/ckfinder/userfiles/files/25599534705.pdfIn PDF document text
    • https://noursportevents.com/wheelmarine/userfiles/file/madipupajopazubavovukajav.pdfIn PDF document text
    • http://blfimmobiliare.com/userfiles/files/10417549.pdfIn PDF document text
    • http://www.buildonhope.org/file/53500326101.pdfIn PDF document text
    • http://aktifimmo.lu/userfiles/files/ximowujidaxurivudabamez.pdfIn PDF document text
    • http://belgium-ex.com/images/blog/file/21971266225.pdfIn PDF document text
    • http://tcihk.com/userfiles/banixipuretepufemowa.pdfIn PDF document text
    • https://grandiosieventinuziali.it/filesUploads/file/13595631342.pdfIn PDF document text
    • http://jinruily.com/UploadFile/file/20210907112501939.pdfIn PDF document text
    • http://dtyxbpzx.com/filespath/files/20210908085314.pdfIn PDF document text
    • https://www.potterycommercials.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16130551d232f9---72287281679.pdfIn PDF document text
    • http://border-collie.ru/sites/default/files/file/valelibasuzemupadako.pdfIn PDF document text
    • https://hotelangela.hu/userfiles/file/93345635119.pdfIn PDF document text
    • http://stroi-sistema.ru/img/42255236986.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161300eb619a1f---womop.pdfIn PDF document text
    • https://pamukoglu.com/userfiles/file/77299643476.pdfIn PDF document text
    • 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_off0000e6cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6CD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fedf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEDF 17236 bytes
SHA-256: 34c4e24eef580b6d7afa5523c69ebee1c03e3ea40bcab2379253507048503e1d
font_02_sfnt_off00012b88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12B88 10868 bytes
SHA-256: 65bc58047a505a5bbc7bcf533ffc4041d2de3cdb4bc439b03712fd18866c6b25