Malicious PDF — malware analysis report

Static analysis result for SHA-256 40d99c89db7019e5…

MALICIOUS

PDF

70.0 KB Created: 2021-09-16 20:35:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e754e6029542fcae78653442a700d4bb SHA-1: 1132271a7dfbbdc1136a49328c9cbcc82b3be0df SHA-256: 40d99c89db7019e5f1487aae7637ae696312eec3065c39177d58bad79af123f5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

This PDF file was identified as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs that point to various domains, many of which appear to be compromised or disposable hosting. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a deliberate attempt to create a link farm, likely to distribute phishing content or malware. The presence of multiple URLs on compromised CMS upload storage further supports this malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9950

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://smidgel.ru/uplcv?utm_term=what+should+i+write+in+subject+when+sending+my+cv+by+email
    • https://serpavenger.com/ckfinder/userfiles/files/89135712035.pdf
    • https://picinterior.com/ckfinder/userfiles/files/2257007328.pdf
    • http://kaies.cn/upfiles/file/22358721798.pdf
    • https://surupaceanu.ro/ckfinder/userfiles/files/jagijugezabesowo.pdf
    • https://sidexsideaudio.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614323c507c05---gezikibifajudewimili.pdf
    • http://folientastaturen.pl/_data/file/38005497063.pdf
    • http://pointerboards.com/uploads/admin/files/57679620196.pdf
    • http://infoegrafica.com/userfiles/files/linamewiwevuzezipewu.pdf
    • https://cian.hr/userfiles/file/lulorasomefikomudujiga.pdf
    • https://www.gs-gleichmann.de/wp-content/plugins/formcraft/file-upload/server/content/files/16137cac25137b---67251031886.pdf
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/161344f9e9d257---69746124894.pdf
    • http://tdbakademi.org/userfiles/files/fapezavikure.pdf
    • https://mtestbd.com/assets/uploads/files/91723690939.pdf
    • https://limpjet.com.br/wp-content/plugins/super-forms/uploads/php/files/b1624081e0f79cf8f8df63f248f83bc4/6224796736.pdf
    • http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614344141d549---23871661266.pdf
    • https://duvarkagidierzincan.com/userfiles/file/70166098863.pdf
    • http://hb-hospital.com/file_upload/fck_upfile/file/zodejaxidere.pdf
    • http://namngonviet.com/user-/files/64440122060.pdf
    • http://leaguengn.com/userfiles/file///sapenom.pdf
    • http://mibenjamin.com/userfiles/file/nenemulapirorutijasir.pdf
    • http://entryexpress.online/chapter_images/files/4245402162.pdf
    • http://wskinbody.com/data/boardData/files/futejumefiwujuv.pdf
    • https://nguyenthelong.net/userfiles/files/44265249798.pdf
    • http://bagiez.com/userfiles/file/rezomaxubaxixugupevoloda.pdf
    • http://ecosdaliberdade.com/ckfinder/userfiles/files/woxoka.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_off0000b273.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB273 16792 bytes
font_01_sfnt_off0000ca85.bin
2a3e47e639b81f2e7ea05eaea45528c621100e1e124580af9eaffe5f8953ab08
pdf-font-stream PDF embedded font (sfnt) at offset 0xCA85 14632 bytes
font_02_sfnt_off0000ef3d.bin
0bde3677d0652dfc57e4b553ff0b1f0968ed2359e58f2b02e21589a1e395a476
pdf-font-stream PDF embedded font (sfnt) at offset 0xEF3D 11444 bytes