Malicious PDF — malware analysis report

Static analysis result for SHA-256 85ab724591e13014…

MALICIOUS

PDF

71.4 KB Created: 2021-09-17 07:52:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 11b03f583e7ff5ad9a70f7ff33fd6167 SHA-1: c62ae12819ee855d430d5eb6d0f22a75bd866d29 SHA-256: 85ab724591e130149a8bb1b9b19a5de1d6211fd63e9008d9818cc6fb34ed338b
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple external links, with a high-confidence heuristic flagging a link to an algorithmically-generated URL. The ML classifier and ClamAV detection strongly indicate malicious intent. The presence of embedded URLs and the PDF structure suggest it's used as a lure to redirect users to potentially malicious sites, consistent with phishing or malware distribution campaigns.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 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.
  • 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://chcial.ru/uplcv?utm_term=how+to+increase+internet+speed+in+mobile+hotspot
    • http://marymo.ru/uploads/files/wusabakisejowodetumof.pdf
    • http://olymp-kiev.com/temp/fckeditor/file/933522807.pdf
    • https://garnizone.com/userfiles/file/fukuza.pdf
    • http://dailyliving.nl/ckfinder/userfiles/files/75852726674.pdf
    • https://contemporaryteas.in/admin/uploads/file/3533427970.pdf
    • http://szamosiszerviz.hu/feltoltott/files/87544780976.pdf
    • https://hssanesteban.cl/files/pivonorukagenovagusuk.pdf
    • http://ketnoikienthuc.com/upload/files/49184800696.pdf
    • http://commandhousecreations.com/uploads/files/18328291935.pdf
    • http://lucidarepavimentimarmogenovaealessandria.it/userfiles/files/zulajojowupuxijunoxu.pdf
    • http://indyskischool.com/ckfinder/userfiles/files/bosolowukomogupokejidi.pdf
    • https://www.iieng.org/editor/ckfinder/userfiles/files/66996513811.pdf
    • https://ikansambel.com/contents/files/8520014971.pdf
    • http://mezon.jp/userfiles/file/doxos.pdf
    • http://akinmedical.com/uploads/file/nejirinetivesodoj.pdf
    • http://cephedanismani.com/images/pages/file/32315637001.pdf
    • http://luligang.com/ckfinder/userfiles/files/38312202802.pdf
    • http://transbur.ru/admin/ckfinder/userfiles/files/posugexigotetofu.pdf
    • https://8foro.exceltur.org/exceltur_nuevo/ckfinder/userfiles/files/nujobesot.pdf
    • https://benmoonpharma.com/userfiles/file/zizewib.pdf
    • http://poiskvod.ru/images/file/petebirubupuwomelapadaja.pdf
    • https://vpmemorial.net/images/file/51051289124.pdf
    • https://sunridgecorp.com/uploads/files/202109061544172792.pdf
    • http://bibikid.ru/upload/kinezegixoxigojit.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b886.bin
dfa91cb6a75195f3be266e1a4d1fc36cd142dc78436d1dde5babcd76ef80fee1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xB886 15060 bytes
font_01_sfnt_off0000de72.bin
6664e9d1a41971c6d4545d74c8128a00be4b1e0a8f83c483afd24600a72f4428		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDE72 10996 bytes
font_02_sfnt_off0000f78f.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF78F 16792 bytes

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