Malicious PDF — malware analysis report

Static analysis result for SHA-256 558a8f5abf08505d…

MALICIOUS

PDF

68.7 KB Created: 2021-10-03 02:18:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: c5a854598dea88b482bd9e23b89af08d SHA-1: 851cfa6473e770802d5c3db92ba6c10fe17fa28b SHA-256: 558a8f5abf08505da129bd0356cc72b589f7fc91b2d3fcfadc81a07901404fb5
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier indicating maliciousness. The presence of numerous embedded URLs pointing to other PDF files suggests a link farm or content distribution scheme. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically highlights the suspicious nature of these links, indicating a potential SEO manipulation or malware distribution tactic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 5

  • 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.
  • 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://kfnmdg.com/upfolder/e/files/20211001050504.pdf In PDF document text
    • http://poketomecam.com/uploads/files/ferubidowepekubumipi.pdfIn PDF document text
    • https://zapret-rf.org/web/img/podborky/files/jaraxupewe.pdfIn PDF document text
    • https://interference.ajoda.eu/userfiles/files/63047651170.pdfIn PDF document text
    • http://zvaracskaskola.eu/editor_uploads/system/files/5583382681.pdfIn PDF document text
    • https://acrgroup.nl/userfiles/file/51552501001.pdfIn PDF document text
    • https://vipbeachhouse.com/uploads/editor/file/xetopiz.pdfIn PDF document text
    • http://racecross.com/upload/edito_fckeditor/file/mawoz.pdfIn PDF document text
    • https://webhostmurah.com/wp-content/plugins/formcraft/file-upload/server/content/files/161529c34850b5---wumugi.pdfIn PDF document text
    • http://mgocsm.in/userfiles/file/33519494161.pdfIn PDF document text
    • http://harasim.cz/uploaded/files/83690192341.pdfIn PDF document text
    • http://solyaris.pro/admin/ckfinder/userfiles/files/17215086483.pdfIn PDF document text
    • https://slotpt2.com/contents/files/juvobo.pdfIn PDF document text
    • http://lifeline-sports.com/files/file/71271361113.pdfIn PDF document text
    • http://countryclaim.cz/userfiles/file/47178493862.pdfIn PDF document text
    • http://eternaseguros.net/files/files/27058903676.pdfIn PDF document text
    • http://zaiger.ru/img/file/86113274153.pdfIn PDF document text
    • http://carzip.biz/files/uploads/files/siwedimi.pdfIn PDF document text
    • https://fullhousetourism.com/UploadFiles/file/20210922192734167.pdfIn PDF document text
    • http://bigcool.net/webroot/img/files/38881180505.pdfIn PDF document text
    • https://medius.sk/userfiles/file/rajufaseti.pdfIn PDF document text
    • http://another-partner.morefriendship.com/upload/files/wopixajadagojupekalawo.pdfIn PDF document text
    • http://waetsukai.jp/system/ckfinder/userfiles/files/xejaridim.pdfIn PDF document text
    • http://natpuedu.in/userfiles/file/jukorewosilosenakagi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=bohr+diagram+first+20+elementsPDF 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_off0000ada0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xADA0 11096 bytes
SHA-256: 8811c5d91e2c961aaec66b3ba6f5110b8b41a126f624ef9c4107f0f6362cf2f3
font_01_sfnt_off0000c72f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC72F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000df41.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF41 15104 bytes
SHA-256: d831ab39f7a6a160fb0d8500b61eb3900c1636facc6f29541cee07c83be2301e