Malicious PDF — malware analysis report

Static analysis result for SHA-256 16b5de5915807cea…

MALICIOUS

PDF

89.8 KB Created: 2021-09-10 03:58:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8b15137e2dbccd854049ffd031d578c1 SHA-1: f469cb1c50db9f84717f21eba1ab9d28d4e378a0 SHA-256: 16b5de5915807cea8798b5e6ccde50055c984411b3c2a4caadf2d0f5961fa925
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many of which are hosted on disposable domains or compromised CMS uploads, indicating a link farm or phishing lure. The ML classifier and ClamAV detection strongly suggest malicious intent. While no scripts were explicitly extracted, the PDF structure and heuristic firings point towards a phishing or malware distribution campaign, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9966

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://crysiq.ru/uplcv?utm_term=make+money+developing+android+apps
    • http://otestmanager.org/club/data/userfiles/file/20210902214927.pdf
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/1612f29f30f634---duwesepenejan.pdf
    • http://www.syrahresources.com.au/application/third_party/ckfinder/userfiles/files/jewaki.pdf
    • http://kahounova.cz/userfiles/file/74495886669.pdf
    • http://bibliotekaludwin.pl/img/upload/files/neleterejodives.pdf
    • http://colafranceschi.it/userfiles/files/94617638058.pdf
    • https://ijtm.in/userfiles/file/21962370122.pdf
    • https://emons-verlag.com/testarea/cwsCMSlight/media/files/43231604297.pdf
    • http://www.zywawiara.pl/pliki/91369264542.pdf
    • http://zh-huaxun.com/uploadfiles/files/ferubonenis.pdf
    • https://rwd1.thadv.com/upload/files/46086938371.pdf
    • http://tdbm.vn/upload/files/64682519017.pdf
    • http://architettorobertafasola.eu/userfiles/files/nuxujokazabixusuzipuram.pdf
    • https://gmonlinestore.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137ebab08769---35515680758.pdf
    • https://athensviptour.com/wp-content/plugins/super-forms/uploads/php/files/5bb7e8bc8779f71cb9e32b2dc9cc247d/xudukoxi.pdf
    • https://adrfarysz.pl/userfiles/file/94206510877.pdf
    • https://hagabb.ro/ckfinder/userfiles/files/lugagodetepedefa.pdf
    • https://adikkedua.com/contents/files/53546131185.pdf
    • https://myclubowners.travelenvogue.com/userfiles/files/wemovupozafifaxuteriguper.pdf
    • http://erbamedica.org/userfiles/files/5440998916.pdf
    • http://partnercable.com/files/4925556835.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_off0000f9ba.bin
f1273aa137b11241f783d6a6f0e5c46cec5e68a65d748865393cdc1c5fb7e246		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF9BA 18208 bytes
font_01_sfnt_off000128f6.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x128F6 16792 bytes
font_02_sfnt_off0001410d.bin
7029b66546f4becacb8eac1f7254c7975cb414ca8929e6bdf5d5ee75136d5508		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1410D 10904 bytes

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