Malicious PDF — malware analysis report

Static analysis result for SHA-256 27c4836c19134d78…

MALICIOUS

PDF

74.4 KB Created: 2021-09-13 06:09:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: a220660e97553099287eed702e3776dc SHA-1: c93843d34bcf0768a707e7803cc2ef5f043833a5 SHA-256: 27c4836c19134d788c9fea43b4ede4af91410c72dd79554638082970c17eae9a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm. Multiple URLs point to compromised CMS uploads or disposable hosting, suggesting a phishing or malware distribution scheme. The PDF structure and embedded content, though heavily obfuscated, are consistent with documents used in phishing campaigns.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 6

  • 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 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 https://philabc.ru/uplcv?utm_term=heavy+truck+simulator+apk+hack PDF link annotation
    • http://bebaldebaran.eu/userfiles/files/77684271543.pdfIn PDF document text
    • http://seoaudytor.pl/userfiles/file/98378135063.pdfIn PDF document text
    • https://infoenergie-loire.org/userfiles/file/55383777239.pdfIn PDF document text
    • http://erh-hu.com/userfiles/file/dutejamafiro.pdfIn PDF document text
    • https://amthanhanhsangchinhhang.vn/upload/files/vekotupugumu.pdfIn PDF document text
    • https://okinawa4d.com/contents/files/sexefujar.pdfIn PDF document text
    • https://mimpidia2.com/contents/files/67622637439.pdfIn PDF document text
    • https://hse.tw/upload/file/fosalesege.pdfIn PDF document text
    • http://shrlie.com/upload_fck/file/2021-9-10/20210910095813267818.pdfIn PDF document text
    • http://dtjxbpzx.com/filespath/files/20210910155355.pdfIn PDF document text
    • https://tapetcenter.ro/app/webroot/files/userfiles/files/julexifux.pdfIn PDF document text
    • https://www.shopveriamici.com/wp-content/plugins/super-forms/uploads/php/files/8fn95tpuk47pd4lnmd42puroo9/nalop.pdfIn PDF document text
    • https://hkfew.org.hk/ckfinder/userfiles/files/mepejetawosenuworeban.pdfIn PDF document text
    • http://jadeite.ru/images/file/sojemosale.pdfIn PDF document text
    • http://drironcat.com/images/file/gutokefixixomovolujifeka.pdfIn PDF document text
    • https://www.prowallpanama.com/wp-content/plugins/super-forms/uploads/php/files/942fcbcd56497a165bad75a861c4658b/88736008490.pdfIn PDF document text
    • https://kolodezrus.ru/wp-content/plugins/super-forms/uploads/php/files/228a9aa47baba3e3b9c1e8199c37866b/40780685178.pdfIn PDF document text
    • https://mfdesign.hu/files/file/bakara.pdfIn PDF document text
    • https://matratva.in/userfiles/file/rowomumuvezirazo.pdfIn PDF document text
    • http://xutricolor.com/uploadfile/files/28039176745.pdfIn PDF document text
    • http://vaonhaphatphap.com/images/uploads/files/mizewituzaganugone.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_off0000bb19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBB19 10896 bytes
SHA-256: 0ebaa4f0e08ec67844cfb120a9a677cbbbaebc763f6906bf96e41f07d08b7452
font_01_sfnt_off0000d459.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD459 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000ec6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC6B 18372 bytes
SHA-256: 61145125ddc4521ec36df5d2d59277471e962e337f25c3ed21493564e9d445fe