Malicious PDF — malware analysis report

Static analysis result for SHA-256 7a91b6dbc7e2c34d…

MALICIOUS

PDF

70.7 KB Created: 2021-09-19 10:01:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 97a2a476083e3ea7ac040e98e53ebd38 SHA-1: 3709d26cf98fab099a2cf44465d82550b5ddc42b SHA-256: 7a91b6dbc7e2c34d00c85c8f673bb3741862656d2dfa47d24efcfcb58f0a678c
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload storage or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. The document body is unreadable due to the authoring application, but the heuristic firings are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://danguykhoidoanhnghiephp.vn/Upload/files/kigeweb.pdf In PDF document text
    • http://doubler-son-capital.com/photos/files/vetejetajemolu.pdfIn PDF document text
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/1612fc38c6e9c0---mamuwenatalozegazone.pdfIn PDF document text
    • https://www.auto-ecole-rive-droite.fr/ckfinder/userfiles/files/domerov.pdfIn PDF document text
    • http://learnazia.com/fck/imagesfile/86043543784.pdfIn PDF document text
    • http://barcabianca.eu/upload/file/3498082500.pdfIn PDF document text
    • https://fenixfalt.com/userfiles/file/66596462889.pdfIn PDF document text
    • http://masan315.net/board/imagefile/file/lomupovalutusa.pdfIn PDF document text
    • http://nhungbaithuocnam.com/img-tvdl/files/masowerepifom.pdfIn PDF document text
    • http://vinag7furniture.com/app/webroot/files/editor_upload/files/wogewemerurijad.pdfIn PDF document text
    • https://webtechnocrats.com/upload/file/68900368710.pdfIn PDF document text
    • https://www.mppoa.cloudlinesystems.com/assets/ckfinder/userfiles/files/tanavuza.pdfIn PDF document text
    • https://seroinstitute.com/wp-content/plugins/super-forms/uploads/php/files/46d2447cd31ff160397bdf0f018daf4c/debiwepazukewebuwiwofaloz.pdfIn PDF document text
    • http://taxilitomerice.cz/ckfinder/userfiles/files/kenonaxivapilawevororimi.pdfIn PDF document text
    • http://medica-brno.com/files/vazovusop.pdfIn PDF document text
    • http://st03.it/userfiles/files/vobizotofow.pdfIn PDF document text
    • http://maturitni-ples.eu/UserFiles/File/wagemufuropofadumagizi.pdfIn PDF document text
    • http://ballarioarchitetti.eu/userfiles/files/wodez.pdfIn PDF document text
    • http://thriftstorewebsites.com/flash/thriftstorewebsites.com/file/xomazowilinamafajokosof.pdfIn PDF document text
    • http://aprt1day.ru/file/nubazitifinokuru.pdfIn PDF document text
    • http://busankid.com/webfiles/board/file///pipudizozomopukivebol.pdfIn PDF document text
    • https://sodigital.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613a61eaa7980---xedoresonoz.pdfIn PDF document text
    • https://felixtrail.com/imagini_ws/puboxesenedixitizumok.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=vola+sports+channelsPDF 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_off0000b6d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB6D8 10348 bytes
SHA-256: ddc59cc6c991cc798b71fcaa4a886d2d1f87b26b9e619763f1c8dbb8d38efec0
font_01_sfnt_off0000ce3f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE3F 15548 bytes
SHA-256: 14f481b4a5d057a70a2c159e6fc32c16ee3c6db12ebe5817edc3ff66424dbfba
font_02_sfnt_off0000f585.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF585 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1