Malicious PDF — malware analysis report

Static analysis result for SHA-256 a33f223b6029cc3c…

MALICIOUS

PDF

85.3 KB Created: 2021-09-20 08:48:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: aa261102d7fc52bc5ed3cdddf97e89dd SHA-1: 267c31c85431e42638c3b91744b046d7ac2fb2fb SHA-256: a33f223b6029cc3ccd62bfcdd5b92790de812199a0cdfc45fac9a4a0761dbcde
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, and exhibits characteristics of a link farm, a common tactic for phishing or malware distribution. The presence of embedded JavaScript and numerous external URIs, many pointing to potentially disposable domains, suggests an attempt to redirect users to malicious sites. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a high volume of links on low-reputation domains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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
  • 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 http://crosswaysrecruitment.com/userfiles/file/28498928091.pdf In PDF document text
    • http://viettelhaiphong.me/data/dulieu/files/19736546882.pdfIn PDF document text
    • http://europeanprofservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16147d52f5a8f6---66807688728.pdfIn PDF document text
    • http://meuble-tunisie.com/userfiles/file/99933828671.pdfIn PDF document text
    • http://homeopathyhk.com/files/napigezoxixolojinumowuxe.pdfIn PDF document text
    • http://laconchigliacasevacanze.it/userfiles/files/65893648860.pdfIn PDF document text
    • http://boldogelet.hu/media/fakarufuzitalafikojaxeti.pdfIn PDF document text
    • http://mulroyenvironmental.ie/userfiles/file/8532249512.pdfIn PDF document text
    • http://paintmaster.hu/js/ckfinder/userfiles/files/66044529652.pdfIn PDF document text
    • http://infrabud.eu/fckpliki/file/fenazunamuvaserote.pdfIn PDF document text
    • https://ht-cooling-j3t.com/contents/files/rawiwizukijodewenob.pdfIn PDF document text
    • http://dj-maily.com/uploads/pages/files/60209419702.pdfIn PDF document text
    • http://deforma.it/userfiles/files/13935208663.pdfIn PDF document text
    • http://emilymillerlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/76451238602.pdfIn PDF document text
    • http://leadershipcareer.kr/fckeditor/_upload/file/xaraxubelenona.pdfIn PDF document text
    • http://mibenjamin.com/userfiles/file/sogeku.pdfIn PDF document text
    • http://termosystem.pl/userfiles/file/97977506813.pdfIn PDF document text
    • http://veterina-hrib.cz/user-uploads/files/mixigaj.pdfIn PDF document text
    • http://zrdb-drogbud.pl/Upload/file/21162972782.pdfIn PDF document text
    • http://linyuepharm.com/upload/files/barexezaku.pdfIn PDF document text
    • https://distriparkbotlek.nl/userfiles/files/3940419737.pdfIn PDF document text
    • http://ocean-ex.com/images/blog/file/pibavofomiwusase.pdfIn PDF document text
    • http://macierz-grodziec.org/files/file/8838406671.pdfIn PDF document text
    • http://taiwan-tsai.com/upload/files/94136869773.pdfIn PDF document text
    • http://bogaarchitetti.it/userfiles/files/mizezarebomajuwuzipo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=developer+options+redmiPDF 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_off0000e959.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE959 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001016b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1016B 18168 bytes
SHA-256: 17885aee1406c350ca9b23e41f27bc9fd7595a033c5c59e732bb055df7e5e659
font_02_sfnt_off0001306d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1306D 10456 bytes
SHA-256: 2de9a678db0c3dfd4558f7ce4c2a66875d402c1c2ddf599325135f9442a2052d