Malicious PDF — malware analysis report

Static analysis result for SHA-256 aca23ab2ac1e778f…

MALICIOUS

PDF

76.4 KB Created: 2021-09-04 18:29:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8279e09ecab8f7c4a8c698c2d4445f81 SHA-1: 76961deacdd088bab5773e6fafe18bd84e79c613 SHA-256: aca23ab2ac1e778fabf61e161547d1d93d2d792628e636238b6aa43c0d1d4dd1
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many of which point to compromised websites or are part of a link farm designed to obscure the true destination. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or redirecting users to malicious content. The use of wkhtmltopdf suggests it was generated programmatically, possibly as part of a larger campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://majorsagilekvaros.hu/uploads/file/2684527619.pdf
    • http://aescantabria.es/upload/fckeditor/file///navijixefodibeduri.pdf
    • http://aci-immobilier-douai.fr/userfiles/files/42340420148.pdf
    • http://osullivanspressurewashing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076db0694e12---54213172319.pdf
    • https://caribemed.com/userfiles/file/82520867277.pdf
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160f42437d9b5c---12806026053.pdf
    • http://iiiemjobs.com/FCK_Editor_Images/files/16682969005.pdf
    • https://aawyx.com/sites/default/imageuser/file/18553117327.pdf
    • http://stalmost.pl/userfiles/file/dowanijopumoxiv.pdf
    • http://bubblesoflove.net/wp-content/plugins/formcraft/file-upload/server/content/files/1607fa835e38ab---1844204749.pdf
    • http://shipsupply.ru/userfiles/files/petadakegunudok.pdf
    • http://www.gametimecatering.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a893d649161---99067461781.pdf
    • https://vaitinhdien.com/app/webroot/upload/files/wibubi.pdf
    • https://www.pharmaright.ca/wp-content/plugins/super-forms/uploads/php/files/ehvuu6ah48ekpa1pnh3cbb4rf0/70953704807.pdf
    • http://www.cerel.eu/images/wyswig_images/file/58206682866.pdf
    • http://studiotecnicopetrillo.eu/userfiles/files/tukakobaravet.pdf
    • https://nusantarabet4d1.com/contents/files/12802787564.pdf
    • https://aurorabersinar2.com/contents/files/99846913611.pdf
    • http://www.sindafaz.com.br/admin/editor/ckfinder/userfiles/files/memasozopajur.pdf
    • https://rockeit.com/userfiles/file/kezepewinu.pdf
    • http://burelomdo.com/ckfinder/userfiles/files/5641276124.pdf
    • http://endustriyelkiralama.com/wp-content/plugins/super-forms/uploads/php/files/hq64etu77vqg9d79tef7110aoo/gibexora.pdf
    • http://xn----9sbbnbtte4cyg.xn--p1ai/ckfinder/userfiles/files/vezomofoj.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=spanish+buffet+menu+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_off0000c421.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xC421 16792 bytes
font_01_sfnt_off0000dc38.bin
6cbe25f7d42a9fb29d8f2ad67d3938fd7273818ee10ebd00a6ce1069efffaa8e
pdf-font-stream PDF embedded font (sfnt) at offset 0xDC38 10812 bytes
font_02_sfnt_off0000f4b8.bin
6f9b70557ba4971ba62c22d50e8193b2c036d71b194426e73f5649720f1f06b8
pdf-font-stream PDF embedded font (sfnt) at offset 0xF4B8 18532 bytes