Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f0835ea44f1365…

MALICIOUS

PDF

80.2 KB Created: 2021-09-14 00:44:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 58d20120167a3f01a65dffaef0305bbe SHA-1: 8e9ea4766feec490c5d92c346e3ac3ebbad8f5b8 SHA-256: 81f0835ea44f13651ae99370d6c526c441a1c430b30adc09176b0d2f95bea14d
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample contains embedded JavaScript, a common technique for executing malicious code within PDFs. It also features a link farm pointing to multiple external URLs, some hosted on compromised WordPress sites, suggesting an attempt to redirect users to malicious content. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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 https://archism.ru/uplcv?utm_term=how+to+draw+graffiti+letters PDF link annotation
    • http://1137.jp/app/webroot/js/ckfinder/userfiles/files/66407536106.pdfIn PDF document text
    • http://sandlnae.com/data/editor/file/pujusatupumuniruwax.pdfIn PDF document text
    • https://cribpointonline.org/cribpointonline/userimages/file/viwapij.pdfIn PDF document text
    • http://getawaynewzealand.co.nz/wp-content/plugins/formcraft/file-upload/server/content/files/161387ce562060---sasulanemixelededuzibow.pdfIn PDF document text
    • http://xn--b1adcbbai1bezln.xn--p1ai/content/File/30826976505.pdfIn PDF document text
    • http://reclaimsplus.com/wp-content/plugins/super-forms/uploads/php/files/90dd8ab0b885127c77538f93028c55e0/bamiwutenuwigupugu.pdfIn PDF document text
    • https://viettincapital.vn/upload/files/6326963685.pdfIn PDF document text
    • https://www.fyna.com.au/application/third_party/ckfinder/userfiles/files/wirazafafek.pdfIn PDF document text
    • https://krainaogrodow.eu/zdjecia/fck/file/pibirajakifagejo.pdfIn PDF document text
    • http://jeykrishnaclub.com/images/file/95403126325.pdfIn PDF document text
    • http://networkinglikepro.com/ckfinder/userfiles/files/67056564562.pdfIn PDF document text
    • https://tailormade-sales-marketing.com/userfiles/file/vakobutope.pdfIn PDF document text
    • http://elma1.ru/!upload/files/foneworamalin.pdfIn PDF document text
    • http://svazekobciorlice.cz/userfiles/file/1278042757.pdfIn PDF document text
    • https://viessmannboilers.ca/fck_upload/file/mujapesogugajil.pdfIn PDF document text
    • http://meble-tk.pl/userfiles/file/konuxu.pdfIn PDF document text
    • http://vhshf.de/File/xureloxiromulo.pdfIn PDF document text
    • http://gruppocreta.com/userfiles/files/pekukugema.pdfIn PDF document text
    • https://korzo-galeria.hu/files/file/wapatog.pdfIn PDF document text
    • https://earthchartercities.org/wp-content/plugins/formcraft/file-upload/server/content/files/16130272dee286---85482358502.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16138e5435c923---lumomuxixabub.pdfIn PDF document text
    • http://ipea.kr/userData/board/file/nofakuj.pdfIn PDF document text
    • http://schroniskoorzechowce.pl/ckfinder/userfiles/files/81650860536.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_off0000d5cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5CD 17624 bytes
SHA-256: dd227968172f8a1e47140232acba762a9dc432a4f9d9d2bb94e96d9c267eee4c
font_01_sfnt_off00010376.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10376 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011b8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B8D 10500 bytes
SHA-256: ecb6663a35e9602b3cfd78ce4a94427daa0e2f0db50fb00b539ce445c97dcbfe

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