Malicious PDF — malware analysis report

Static analysis result for SHA-256 878f8fbbd6da0a37…

MALICIOUS

PDF

81.4 KB Created: 2021-10-16 05:30:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-03
MD5: c29be7789846faa89886f9e31d6738d5 SHA-1: f4d9106e253920e85ab1f06bc19a0b1d5c325f66 SHA-256: 878f8fbbd6da0a375521c0e24fa92837a5aa2fec87c84b976a15bbb45de4e856
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links pointing to external resources, many of which are hosted on compromised websites or disposable domains, indicating a link farm designed to redirect users to malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution. No scripts were extracted, but the heuristic firings indicate the PDF itself is structured to facilitate the download of further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 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://theshop24.com/userfiles/file/kigugesetupal.pdf In PDF document text
    • https://www.wsbe17hongkong.hk/_bin/ckfinder/userfiles/files/85631692141.pdfIn PDF document text
    • https://maturana.cl/upload/file/neranazewugipivawupo.pdfIn PDF document text
    • https://internationallanguagenavigators.com/media/82158400285.pdfIn PDF document text
    • http://bluestandard.pl/ckfinder/userfiles/files/pupigorigoxavu.pdfIn PDF document text
    • https://jnnjhansi.com/userfiles/file/52266260271.pdfIn PDF document text
    • https://hotararicedo.ro/files/files/19556535337.pdfIn PDF document text
    • http://retrievers.su/ckfinder/userfiles/files/wisuvasenokukekite.pdfIn PDF document text
    • http://xn--90ad5ackt1d.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/b31efee1ed09d6c404a52f44ed9d1cfa/jujoxalaje.pdfIn PDF document text
    • http://b40555.handyfriendship.com/upload/files/pufexose.pdfIn PDF document text
    • http://circuitvietnamcambodge.com/hinhanh/file/romumebovegofin.pdfIn PDF document text
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/1614791b572feb---89043862325.pdfIn PDF document text
    • http://badaranquehablar.com/userfiles/files/lorozo.pdfIn PDF document text
    • http://sfssolution.com/userfiles/file/49087794326.pdfIn PDF document text
    • http://outspokenholland.com/userfiles/fckFile/20210922224941.pdfIn PDF document text
    • http://westernmaki.com/uploads/files/28936844548.pdfIn PDF document text
    • http://vibrobeton.by/pics/files/lijexoro.pdfIn PDF document text
    • http://slsnn.ru/content/file/64431416222.pdfIn PDF document text
    • http://iranjobex.com/cache/fck_files/file/4949128861.pdfIn PDF document text
    • http://datacomsystems.cz/userfiles/file/83740493287.pdfIn PDF document text
    • http://makaeximworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614b6074d92a5---rabakolesubuzirajewipu.pdfIn PDF document text
    • http://dainichiji.com/upload_ckr/files/66121442540.pdfIn PDF document text
    • https://shidoremicrosys.com/media/63825013582.pdfIn PDF document text
    • https://doanhnghiepvietnam.org/img_duhoc/files/matano.pdfIn PDF document text
    • http://feedproxy.google.com/~r/MbOu/~3/HTGXzuRVGb4/uplcv?utm_term=likes+and+dislikes+board+gamePDF 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_off0000d87e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD87E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f090.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF090 18288 bytes
SHA-256: 2b1deae200cc4d3a4ffb120c92b696e66ab9ac5247adcd2485f09203e42bbb15
font_02_sfnt_off0001204a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1204A 10684 bytes
SHA-256: 2a8a1995dfd861640f46c4b4968549b5bc49153ecdc0f826f36721ccbb04cba9