Malicious PDF — malware analysis report

Static analysis result for SHA-256 355d16402a967898…

MALICIOUS

PDF

100.4 KB Created: 2021-07-08 01:12:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: f1c4e21e167f65d197074a402cf38ea9 SHA-1: d7b6661bbe73e5e2efae5185e27781d564b9f221 SHA-256: 355d16402a9678981b67952ce5865c09d17105171bed742c1cf39ad204ec2e17
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ML classifiers and ClamAV, indicating it's a phishing or trojan PDF. It contains numerous embedded URLs, many pointing to compromised WordPress sites, suggesting a link farm designed to redirect users to malicious content. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a tactic to obscure the true destination. No scripts were extracted, but the embedded URLs are the primary indicators of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9872

Heuristics 6

  • 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.
  • 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://garglob.ru/uplcv?utm_term=chapter+3+worksheet+answers PDF link annotation
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/0p8qfmkqabqr8ej26d4dpmrsf6/gakaxetavovonobudarawuwi.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab7b6416acd---80113146879.pdfIn PDF document text
    • http://sakirnoopo.ru/wp-content/plugins/super-forms/uploads/php/files/68804dfc7e265f2c7782bdd2861e5b5d/diwuligaretolilibipux.pdfIn PDF document text
    • https://christianboudreau.com/wp-content/plugins/formcraft/file-upload/server/content/files/160baf169f243b---44946616559.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/6802288877b252ebb2dd0a5034be8db5/difuwol.pdfIn PDF document text
    • http://sgrappresentanze.eu/userfiles/files/fumafogokokasagujuj.pdfIn PDF document text
    • https://luxurytravel-show.com/wp-content/plugins/super-forms/uploads/php/files/50b1e0a4282bff3b441867c22c0e9a10/tuduvifawajar.pdfIn PDF document text
    • http://sacoorhealth.pt/site/upload/file/satokizunom.pdfIn PDF document text
    • http://mouaumfb.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a88f6abe25a---sariruwopotudakipudenamun.pdfIn PDF document text
    • http://maihome.hu/admin1/file/ramojox.pdfIn PDF document text
    • http://pmdrecycling.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c77d022c061---wufejazanolavijuzasusiw.pdfIn PDF document text
    • https://ludifrance.fr/userfiles/file/40997866443.pdfIn PDF document text
    • http://geoplan.su/userfiles/file/masalatenizi.pdfIn PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/160aec5fc33b66---nedutukilimijowoso.pdfIn PDF document text
    • http://alpha-th.com/userfiles/file/22604627446.pdfIn PDF document text
    • http://matsusushionline.com/uploads/files/zazinanepejemem.pdfIn PDF document text
    • http://adoriantarla.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160c8da794e57c---87574749908.pdfIn PDF document text
    • https://amenajarisiconstructii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160906b97ed861---20955364623.pdfIn PDF document text
    • https://audreyheselmans.com/_files/file/rilebuvefexerigegogaki.pdfIn PDF document text
    • http://cintabogor.com/Uploads/userfiles/files/5347822692.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075c59a6f88e---60320767363.pdfIn PDF document text
    • https://www.herewardcarpets.co.uk/wp-content/plugins/super-forms/uploads/php/files/8l6m63uafr4os0kvv1ludn9rrb/64310201206.pdfIn PDF document text
    • http://rentbucharest.net/images/userfiles/sisojesebolar.pdfIn PDF document text
    • http://meta-min.com/files/63936463097.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010c7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C7D 16132 bytes
SHA-256: eb83fb48a2f60ac59fad768156047f025764cad4052c8f34695a9c8dd2456ad8
font_01_sfnt_off000121ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121EA 18556 bytes
SHA-256: cd7b7523ffac13de1b41df19da65b9e7d9e0af44425d05892af4ec714ae1fe84
font_02_sfnt_off00015359.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15359 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off00016b70.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16B70 10592 bytes
SHA-256: f5f2f59829dfbfbd865f37b19e92fb016f54585eff3a97ed3307bb3e9801d302