Malicious PDF — malware analysis report

Static analysis result for SHA-256 2a7ce20db39a5dbf…

MALICIOUS

PDF

76.5 KB Created: 2021-09-25 22:13:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4398ad42de775ef881b29a092f02a815 SHA-1: ecf0970dfde86a43e9b38107c26473ca954733c7 SHA-256: 2a7ce20db39a5dbfa1be87b4414f78ee69c4c67c9fd8ef70cd3578e97459786b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it functions as a link farm on potentially compromised or disposable hosting. The embedded URLs, such as 'https://crysiq.ru/uplcv?utm_term=siri+apk+android', suggest a lure to download potentially malicious content. Although no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with phishing or malware distribution campaigns, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

Heuristics 6

  • 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 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://crysiq.ru/uplcv?utm_term=siri+apk+android
    • http://chinastom.ru/userfiles/file/41817651316.pdf
    • http://headlinesdinerla.com/uploads/files/veborokubovonopurike.pdf
    • http://www.scmphotography.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161480ae586d55---zurarugisukuropekajulum.pdf
    • https://lotusmarinevn.com/upload/files/83340592578.pdf
    • http://gr-chem.com/upload/files/31793377801.pdf
    • http://latiendasegura.com/contable_prueba/userfiles/file/12070020602.pdf
    • http://chunmianxian.com/upfolder/e/files/20210923000714.pdf
    • http://imobilestore.de/userfiles/file/75494407573.pdf
    • https://torrentclub.vip/wp-content/plugins/super-forms/uploads/php/files/canatob8muqfs4braaql3kgqo5/rabekop.pdf
    • http://srihemkuntschoolint.com/slbdavbatala/userfiles/file/20312953270.pdf
    • http://lavalnerina.it/userfiles/file/41128549757.pdf
    • https://tailormade-sales-marketing.com/userfiles/file/fetubudaxizazikawusile.pdf
    • https://laetitiabernard.fr/images/file/68883462126.pdf
    • https://www.bluegreenshouseboats.in/wp-content/plugins/formcraft/file-upload/server/content/files/16137fe4c18123---65288437641.pdf
    • https://vcvscr.cz/www/www/fckphotos/file/tefefa.pdf
    • http://malagi.pl/user-files/fck/file/tofonibubafakadizowesad.pdf
    • http://adamlegal.com/userfiles/file/62797330749.pdf
    • http://autolubitel-irk.ru/userfiles/file/84347469457.pdf
    • https://gesema.com/UserFiles/file/zefiborekuranetudavo.pdf
    • http://medicaldistri.com/ckfinder_files/files/zefagunazewinarusanulef.pdf
    • http://zaragozalawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/lukazusavejisisexuzotaw.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000be1c.bin
bc570b9f5431fceede59b5cdfc3e96eaddbf20d393c2129fd907d379fe82f75c
pdf-font-stream PDF embedded font (sfnt) at offset 0xBE1C 10108 bytes
font_01_sfnt_off0000d4a6.bin
9bbf9196444f45e2945ea9f8758590f30186b04622549b747e54c185598086c0
pdf-font-stream PDF embedded font (sfnt) at offset 0xD4A6 21836 bytes
font_02_sfnt_off00010c9a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10C9A 16792 bytes