Malicious PDF — malware analysis report

Static analysis result for SHA-256 856aa638977ee614…

MALICIOUS

PDF

83.3 KB Created: 2021-09-01 12:15:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: df3f7af5d56ddb382b1d7653224714e8 SHA-1: 2f92fdae8aaf2b2b869f401bc4e7881b2841ed24 SHA-256: 856aa638977ee614ff789558932058610d46ea1e828d18a961d1a8abd9e9880d
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple links pointing to external resources, many of which are hosted on compromised WordPress sites or disposable domains, indicating a link farm designed to distribute malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware delivery. No scripts were extracted, but the PDF structure itself is used to facilitate the attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9934

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • 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 http://duda-tech.pl/dudatech/upload/file/69292664779.pdf In PDF document text
    • http://duetsepolno.pl/userfiles/file/kegusesosivig.pdfIn PDF document text
    • https://goldgreiner.de/userfiles/file/63950947898.pdfIn PDF document text
    • http://manisafar.com/basefile/marcosafarir/files/radujefupozopabikuv.pdfIn PDF document text
    • https://valubil.com/public/uploads/cms_file/cms_files/xubopovutifexiwunepipug.pdfIn PDF document text
    • https://neoville.ru/wp-content/plugins/super-forms/uploads/php/files/f94c069a77182ae9e42f2216cdd98c50/viwubexawekep.pdfIn PDF document text
    • http://istanbulballoons.com/ckfinder/userfiles/files/21398329098.pdfIn PDF document text
    • https://artasedanasingaraja.com/uploadfck/file/30335838914.pdfIn PDF document text
    • http://baliretreatcenter.com/olabali_ci/media/images/newsfiles/nabatobuvopumokaravome.pdfIn PDF document text
    • https://1sis.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081cbab628aa---73653431593.pdfIn PDF document text
    • http://wypelnienia.kratex.pl/wp-content/plugins/super-forms/uploads/php/files/fd08ebb9f8f29448dcf7fc7aa7d12367/godasofapavavezutegepopum.pdfIn PDF document text
    • https://porterbrothersltd.com/app/webroot/uploads/4296880535.pdfIn PDF document text
    • http://media-production.net/admin/ckfinder/userfiles/files/tunagutapipej.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16097fe2fe344b---malusirikavomev.pdfIn PDF document text
    • https://alternatifhosting.com/calisma2/files/uploads/sunoverumopetevukis.pdfIn PDF document text
    • https://thediamangroup.com/_images/files/77113969991.pdfIn PDF document text
    • https://hylyt.co/wp-content/plugins/super-forms/uploads/php/files/f0e2b8b9ca64bf263fd8d3ef37434551/depobawuzevon.pdfIn PDF document text
    • http://vaughanreunion.com/clients/7/7c/7cfe0b8ff6d5e3136a6575a9b258a09c/File/dojamasetoxikinup.pdfIn PDF document text
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160c0fe427e2fb---xajuxatune.pdfIn PDF document text
    • https://superiorservicesandsolutionsfl.com/nbloom/fckuploads/file/bukaniperusibuze.pdfIn PDF document text
    • http://triumphtoday.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a7f70967bea---pojatu.pdfIn PDF document text
    • http://julieesteban.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a469ba93ead---xutefomawitokewa.pdfIn PDF document text
    • https://teenvolunteerdallas.org/wp-content/plugins/super-forms/uploads/php/files/7be19d15e13e844b0b30973cc31323fc/zubow.pdfIn PDF document text
    • https://inverpalmas.com/aym_image/files/15500274497.pdfIn PDF document text
    • https://aarhuskortet.dk/images/file/31842284045.pdfIn PDF document text
    • http://abwessex.com/uploads/files/61702920149.pdfIn PDF document text
    • http://ceskylakros.cz/userfiles/file/tabifobugokix.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=sql+data+replication+between+two+serversPDF 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_off0000e00e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE00E 11020 bytes
SHA-256: 9428b525f670e5469cb94e380674c390e15e0330154d514d11976edf3269a76e
font_01_sfnt_off0000f95f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF95F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011171.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11171 17716 bytes
SHA-256: 0ae08283f9c6c71493789dd20c1bf4800229cbe49a7bf95685b12fcab04c776d

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