Malicious PDF — malware analysis report

Static analysis result for SHA-256 c524579b2952ee4e…

MALICIOUS

PDF

82.4 KB Created: 2021-09-20 00:54:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 196f5ff4bcc9e497b4b3062c65d0c135 SHA-1: 652b94843c5c06776fa9ddbe4d44fae4c7f2c929 SHA-256: c524579b2952ee4efd79551bcab23f6982de00ac696a378c1ebc073ed70306be
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of embedded URLs, many of which point to compromised WordPress upload directories or are hosted on disposable domains, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the presence of multiple compromised CMS upload links suggests an attempt to distribute malicious content or phish for credentials. No scripts were extracted, but the overall structure and URL analysis point to a malicious intent to lure users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 5

  • 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://coretry.ru/uplcv?utm_term=how+to+change+display+name+in+gmail+on+android+phone PDF link annotation
    • http://instalace-charvat.cz/userfiles/file/44117266614.pdfIn PDF document text
    • http://easternhoteljeju.com/FileData/ckfinder/files/20210915_C5DF2BC6B1CD598F.pdfIn PDF document text
    • https://dacola.com/upload/files/68404571968.pdfIn PDF document text
    • https://sintasyapi.com/img/userfiles/file/84647872684.pdfIn PDF document text
    • https://jpjplumbingandheating.com/FCKeditor/file/mutosozolezevobuwuputeju.pdfIn PDF document text
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/16143765da13ab---33764683250.pdfIn PDF document text
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613db7122ece1---fipafoxafitod.pdfIn PDF document text
    • http://wasserentkalkung.at/ckfinder/userfiles/files/67757661936.pdfIn PDF document text
    • http://desushibar.com/userfiles/file/juwotipegepuposo.pdfIn PDF document text
    • https://www.cylinder96.ru/admin/ckfinder/userfiles/files/4527904037.pdfIn PDF document text
    • https://luatsubienhoa.com/upload/ck/files/riwegavebufedaliwo.pdfIn PDF document text
    • http://unityproductions.com/upload/files/85198817689.pdfIn PDF document text
    • http://ideal-site.ru/userfiles/file/pirunukonobobaju.pdfIn PDF document text
    • https://interativacorretora.com/fotosempresa/files/pumisekexixu.pdfIn PDF document text
    • https://aymsoft.us/aym_image/files/rujifopuz.pdfIn PDF document text
    • https://braveathlete.net/geektic/files/kuvikijeropom.pdfIn PDF document text
    • http://osullivanspressurewashing.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c6d07822e7---jikarumexo.pdfIn PDF document text
    • http://turskazka.ru/ckfinder/userfiles/files/95768449312.pdfIn PDF document text
    • http://karthikeyanjayaram.com/userfiles/file/lopivusixeb.pdfIn PDF document text
    • http://library.nesdb.go.th/ic/admin/ckfinder/userfiles/files/72994275582.pdfIn PDF document text
    • http://chapelguild.com/images/usr/98429281624.pdfIn PDF document text
    • https://red-adlay.com/upload/files/83131925704.pdfIn PDF document text
    • https://ahl2005.com/ckfinder/userfiles/files/gapetujerurewufukujojaj.pdfIn PDF document text
    • https://study-abroad-travel.com/ckfinder/userfiles/file/kituragubokun.pdfIn PDF document text
    • https://satbietthu.com/luutru/files/xofajenekozilisapebo.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_off0000dc84.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC84 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f496.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF496 17476 bytes
SHA-256: cc7b5a01d08fa4a7c3198720df5ce07913463032cb87e51c44d68cd9e760c322
font_02_sfnt_off00012186.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12186 11152 bytes
SHA-256: c09e7388970e2ee5814978e07e3457921a83f242f768f194cfc7f005681191ab

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