Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f0548a75ca6ddd…

MALICIOUS

PDF

80.7 KB Created: 2021-09-18 02:19:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 36704b3c499178e49bbab14d76009773 SHA-1: a876918c9a0d32ec040a005b181f3e95daf8761b SHA-256: 81f0548a75ca6ddd1437cdbd73dff91a385231ff7edeab5c2e6470957461fe40
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript, which is a common technique for exploiting PDF vulnerabilities or redirecting users. Multiple heuristics indicate the PDF is part of a link farm, with many external URIs pointing to potentially compromised or disposable hosting. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

Heuristics 7

  • 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.
  • 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://brucemayrockinstitute.com/assets/ckfinder/core/connector/php/uploads/files/nifuseretebuziwuwe.pdf
    • https://at-studio.tw/app/webroot/userfiles/files/20210909_163802.pdf
    • http://yksskj.com/ckfinder/userfiles/files/79460580342.pdf
    • http://www.gpe-el.pro/ckfinder/userfiles/files/9107090199.pdf
    • http://fese.in/ienupdimages/images/files/robaguditin.pdf
    • https://pielinks.com/UserFiles/file/pofixuvubagazuzen.pdf
    • https://gulertrafik.com/wp-content/plugins/super-forms/uploads/php/files/i1msntjc6qc3a8279sveu7sujc/baderojejolukunedugizapo.pdf
    • http://sindikat777.ru/ckeditor/ckfinder/core/connector/php/uploads/files/fevebavafutizavib.pdf
    • http://tipkeo.com/js/ckfinder/userfiles/files/91890988089.pdf
    • http://vandientuchinhhang.com/upload/files/36140826793.pdf
    • http://saothienemb.com/uploads/images/files/wiretagojixuwusatunaguruj.pdf
    • http://debten.net/UserFiles/File/24630710013.pdf
    • https://hzautomatisering.nl/userfiles/file/kepuwipiruwukitunezet.pdf
    • https://dungcuruamui.com/wp-content/plugins/super-forms/uploads/php/files/oeksrb6udqdg8e7r8tqd0the72/54590633158.pdf
    • https://leo.tw/upload/ckeditor/files/nafejizaje.pdf
    • http://www.romanschatztruhe.de/img/files/rufade.pdf
    • http://ellev.fr/upload/files/werew.pdf
    • https://arhstroi.by/uploads/files/59850894995.pdf
    • http://effektfilm.de/files/file/88586033665.pdf
    • http://gaia-onlus.org/userfiles/file/wuvofofanowopulofeno.pdf
    • http://sinosteelcode.com/filespath/files/20210917040115.pdf
    • http://fst-uinsu.net/userfiles/files/linadobexafuxur.pdf
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b4fc7480d2.pdf
    • http://vincityhomes.vn/wp-content/plugins/super-forms/uploads/php/files/435vgnru479ecedi4ot6cjvpsi/padibisozin.pdf
    • http://pol2-simf.ru/userfiles/file/wumopavedizuxibeno.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=android+1+dream+league+soccer+2020+hack
    • 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_off0000d167.bin
603b6844a8eedfcd74d33ba6620c6dd30b7bacbbf8503ee3fe954dce18738f8e
pdf-font-stream PDF embedded font (sfnt) at offset 0xD167 19088 bytes
font_01_sfnt_off0001036d.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1036D 16792 bytes
font_02_sfnt_off00011b84.bin
346b020c47efed91b8ef7202a747e2b78f9978a79a23e85bbe0238378a524aaa
pdf-font-stream PDF embedded font (sfnt) at offset 0x11B84 11184 bytes