Malicious PDF — malware analysis report

Static analysis result for SHA-256 b51b349cb83db80e…

MALICIOUS

PDF

82.5 KB Created: 2021-09-22 12:37:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: ff725e1921d5fc02c334caffad2534a0 SHA-1: 4cbf7344ec198cc26558a68026aedc2a92a295bb SHA-256: b51b349cb83db80e1a8ec231b3439300a2fc75096ec8246c0a7829c00a163285
142 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external URIs pointing to link farms on disposable hosting, suggesting an attempt to trick users into downloading malware. The ClamAV detection and ML classifier strongly indicate malicious intent. The presence of embedded JavaScript (T1059.007) further supports the malicious nature of the document, likely used to facilitate the download of a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://askisan.com/upload/ckfinder/files/xulelovemawukutef.pdf In PDF document text
    • http://leebyunghun.org/new/upload/board/files/pisadudodofevum.pdfIn PDF document text
    • http://12shio5.com/contents/files/xuwajibepuv.pdfIn PDF document text
    • https://duhocblueocean.vn/ckfinder/userfiles/files/2446368200.pdfIn PDF document text
    • http://bsa.by/ckfinder/userfiles/files/44014583652.pdfIn PDF document text
    • https://australiancaravancentre.com.au/application/third_party/ckfinder/userfiles/files/76959664209.pdfIn PDF document text
    • http://xn--80aaae7amexjfdlfdfg.xn--p1ai/files/file/fijosolitumakikolomaj.pdfIn PDF document text
    • https://tutorbolivia.com/userfiles/file/2430095011.pdfIn PDF document text
    • http://nemochem.cn/upload/files/bodukebebuxuzatowuposovu.pdfIn PDF document text
    • https://mobile-translator.eu/app/webroot/media/files/81173710072.pdfIn PDF document text
    • http://smart.sut.ac.th/tsme/src/lib/ckfinder/userfiles/files/85527666147.pdfIn PDF document text
    • http://tolltisztitas.eu/userfiles/files/xuriwaponuxunepevejagopot.pdfIn PDF document text
    • http://usa-ex.com/images/blog/file/66870078438.pdfIn PDF document text
    • http://katyababash.com/images/uploads/file/pafemuramit.pdfIn PDF document text
    • https://curewelldiabetes.com/userfiles/file/19935158541.pdfIn PDF document text
    • http://mobilesamara.com/img/files/file/nozokezaliwegafawuvisiv.pdfIn PDF document text
    • https://almudenafernandez.co/ckfinder/userfiles/Files/36010053226.pdfIn PDF document text
    • https://satesayap.com/contents/files/89179208687.pdfIn PDF document text
    • http://pelejas.com/IMAGENS/CKFINDER/files/mivexuwe.pdfIn PDF document text
    • http://staractivecollection.com/resimler/site/files/86269808073.pdfIn PDF document text
    • https://thewentworthco.com/wp-content/plugins/super-forms/uploads/php/files/dc8rg4tpn0442h738g62bgjahp/1868659539.pdfIn PDF document text
    • http://battlegrouponline.com/app/webroot/js/ckfinder/userfiles/files/vozuvawodujam.pdfIn PDF document text
    • http://pengyou-english.com/FileData/ckfinder/files/20210913_46D8CA554BEF5366.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=gta+san+andreas+apk+file+free+downloadPDF 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_off0000d956.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD956 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f16d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF16D 10708 bytes
SHA-256: 58f88c3f2ac782eb9ca731a193ed83a50212928d639663b62e437a3d481a8e04
font_02_sfnt_off00010a30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A30 19200 bytes
SHA-256: 41987f8862a6d8ae0b5097fe0a5887e045a69fc5ecc63e724a984183b3279d42