Malicious PDF — malware analysis report

Static analysis result for SHA-256 31f5d54c7d79e840…

MALICIOUS

PDF

74.5 KB Created: 2021-09-17 23:12:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 6fa65faa70012b2580a55feac91dc1b1 SHA-1: 18f5cd9831c872a965dc7e72bae9e5d2d0c7ab9b SHA-256: 31f5d54c7d79e840904e78e16c5d57ca5ce75c03f0993f3d04692b5b6e641f10
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Analysis reveals it functions as a link farm, with numerous embedded URLs pointing to potentially compromised websites. These links are likely intended to lure users into downloading further malicious content or to manipulate search engine rankings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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 http://enjoyisagenix.com/ckfinder/userfiles/files/85184915128.pdf In PDF document text
    • http://montoaneli.com/ckfinder/files/ropul.pdfIn PDF document text
    • http://winterwonderlandzundert.nl/uploadimages/files/tarofuzevemezavube.pdfIn PDF document text
    • http://arsvet.ru/img/upload/wawaw.pdfIn PDF document text
    • https://www.bocamvigliesrooms.com/wp-content/plugins/super-forms/uploads/php/files/420e179964da3d9f264e3826fd3d7cbe/kedamidasajuzatibufegeteb.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fb34b4e4f7---84360444321.pdfIn PDF document text
    • http://allier-genealogie.org/File:/91864344912.pdfIn PDF document text
    • https://foodvellythailand.com/upload/files/46396324812.pdfIn PDF document text
    • http://www.gyndoktors.de/ckfinder/userfiles/files/70424860626.pdfIn PDF document text
    • https://jechrina.gr/FCKeditor/userimages/file/639503411.pdfIn PDF document text
    • https://archcosmeticstudio.com.au/wp-content/plugins/super-forms/uploads/php/files/281b856521e6a474d7fcfc9a8470bc8f/37130134022.pdfIn PDF document text
    • https://vico-inmobiliaria.com/ckfinder/userfiles/files/godezeriduruvebolufij.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/1613f24f6cc544---lamonofamirakidezadi.pdfIn PDF document text
    • https://cooperspick.com/files/54742153882.pdfIn PDF document text
    • http://szm.hu/userfiles/file/fazuzunarafozasozidebew.pdfIn PDF document text
    • http://polenes.cl/userfiles/file/36379728223.pdfIn PDF document text
    • http://magnumprint.ru/upload/files/dufimatijogijutesiva.pdfIn PDF document text
    • http://primeasset.hu/fileok/file/dagajobuperovowalak.pdfIn PDF document text
    • http://queuemanagementsystems.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134cac17dacc---rumatileki.pdfIn PDF document text
    • http://euro-ex.com/images/blog/file/19738234395.pdfIn PDF document text
    • https://volgogradexpo.ru/ckfinder/userfiles/files/73247632104.pdfIn PDF document text
    • http://trevelsi.ru/ckfinder/userfiles/files/tidijaxekezuzaw.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=how+do+you+send+a+group+text+on+androidPDF 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_off0000beaf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBEAF 17296 bytes
SHA-256: 707cc8bae25697aafd17a8a8b4ee229ee23b020e18fb6288b39a4a3cace897e8
font_01_sfnt_off0000ead9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAD9 10916 bytes
SHA-256: 9a77ca8cdbd8c2ce93aa1e1aafc2b13def501be8f9ea2c16734f74ed19800fd2
font_02_sfnt_off0001041b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1041B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1