Malicious PDF — malware analysis report

Static analysis result for SHA-256 efd6733ef48f26d1…

MALICIOUS

PDF

77.1 KB Created: 2021-09-21 14:01:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f971317eb0ae174b9a57ec7ccf79b0fa SHA-1: d164629aadcff2afdce318e76e3d90b667981bb9 SHA-256: efd6733ef48f26d18d834dc7ebcea030bbf8a2fe688ca6dff79dd048d5f9eef7
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ML classifiers and ClamAV, indicating a high probability of malicious intent. It contains embedded JavaScript and a significant number of URLs, many of which point to compromised CMS uploads or disposable hosting, suggesting a link farm designed to redirect users. The presence of embedded JavaScript points to T1059.007, and the overall nature of the document suggests it was likely delivered as a spearphishing attachment (T1566.001).

Machine Learning

  • Nyx PDF Classifier malicious score 0.9943

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://kralpin.com/calisma2/files/uploads/43787944911.pdf In PDF document text
    • https://onthespothousing.com/userfiles/file/kelajufowix.pdfIn PDF document text
    • http://rymwid-training.com/userfiles/file/3590676240.pdfIn PDF document text
    • https://brs.jo/userfiles/files/3441892138.pdfIn PDF document text
    • https://nffcd.org/userfiles/files/lemuvixavorivakijutiwago.pdfIn PDF document text
    • http://home-plast.ru/foto/files/rimewajixurerefufifividi.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/98dc0302eea96ebc21c4acf383c1efd4/31653259264.pdfIn PDF document text
    • http://edins.net/userData/ebizro_board/file/36290092099.pdfIn PDF document text
    • https://dveropolis.ru/upload_picture/woxisazukafabikakezenim.pdfIn PDF document text
    • http://nhatminhtrading.vn/app/webroot/uploads/files/95168435878.pdfIn PDF document text
    • http://makaeximworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/161443f816b98a---73456978580.pdfIn PDF document text
    • https://olterus.org/contents/files/87285180723.pdfIn PDF document text
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1613f1e43e6f94---saxizokosinazogil.pdfIn PDF document text
    • https://novinfasteners.com/userfiles/file/31953228954.pdfIn PDF document text
    • http://haphadoor.com/upload/files/vodaxokisisujemag.pdfIn PDF document text
    • https://medgal.pl/admin/ckfinder/userfiles/files/1344857535.pdfIn PDF document text
    • http://geojeoceanhotel.com/userfiles/file/20210904075051.pdfIn PDF document text
    • http://dent-pro.cz/pic/file/nukumeburupotesexop.pdfIn PDF document text
    • https://coffotea.com/uploads/files/202109011218588427.pdfIn PDF document text
    • https://bankkartya.hu/js/ckfinder/userfiles/files/12905044238.pdfIn PDF document text
    • http://serendipityorlando.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613642f7e72f1---87987011512.pdfIn PDF document text
    • https://tonerihned.cz/userfiles/file/83361183303.pdfIn PDF document text
    • http://xn--2e0b30g3uq7pay7m.com/upload/fckeditor/file/zobokofugi.pdfIn PDF document text
    • http://hingliltd.com/userfiles/93910478949.pdfIn PDF document text
    • http://resetimpianti.it/reset/public/file/bilozufokegedez.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=best+high+graphics+games+for+android+under+500mbPDF 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_off0000c648.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC648 17548 bytes
SHA-256: 519bb1791b2d6cabd16e43a2192d690b71f67e79bd803bb86fdf25f5d084fb7d
font_01_sfnt_off0000f343.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF343 11572 bytes
SHA-256: 5de124c7cecc415067113508f4e77cced15dc791e374368c23caad95dbfd1d96
font_02_sfnt_off00010e34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E34 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1