Malicious PDF — malware analysis report

Static analysis result for SHA-256 f892b2f599a8aa4c…

MALICIOUS

PDF

81.9 KB Created: 2021-09-22 23:53:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 3eab2264c90357eb64a5053ff796ca8c SHA-1: 31a2d6b76b829a540524529e7ef6227427b0f940 SHA-256: f892b2f599a8aa4c217213b19502413ce0b9907deedd5afe1073141de6995b02
144 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and multiple links pointing to external resources. The heuristics indicate a link farm strategy, with several links hosted on compromised WordPress sites or disposable domains, suggesting an attempt to redirect users to malicious content. The ML classifier strongly flags this PDF as malicious, supporting the conclusion that it is designed to distribute further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 7

  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://letsfinal.com/userfiles/file/nojetodad.pdf
    • https://mytalk7.com/_UploadFile/Images/file/54636340288.pdf
    • https://bi-kiesabbau.de/cmsimple/images/file/65673457096.pdf
    • http://www.hypnotiseur.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139c70a35803---gexipipimajur.pdf
    • https://xn--80apefbdm9ah5g.xn--p1ai/userfiles/20936685231.pdf
    • http://prmakeup.com/Image/files/depapit.pdf
    • https://snabavto.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f3af153e26---46053456780.pdf
    • http://tbff-bygg.se/img/files/likokujifu.pdf
    • http://italiangreyhound.pl/img1/userfiles/file/13700934801.pdf
    • https://alebusph.centralcms.cloud/galeria/files/nivinubejenolodananogob.pdf
    • https://ispartaorganizasyon.com/ckfinder/upload/files/27251188564.pdf
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/61359050119.pdf
    • http://lienming-rubber.com/uploads/files/202109082051104269.pdf
    • https://condicionamentofisico.com/arquivos/file/79857739782.pdf
    • https://reaga.net/js/ckfinder/userfiles/files/gufeguduserikunotoz.pdf
    • https://suavitinhtannha.net/upload/files/kuwivimatafokexemajemuz.pdf
    • http://rubensova16.cz/files/file/xifukubovavipuvituga.pdf
    • https://cullinanconstruction.com/wp-content/plugins/super-forms/uploads/php/files/p5umjk99mn0dkfr30vmfrg56p5/32785301548.pdf
    • https://sunarchegypt.com/userfiles/file/xixisusuzuxefoxowasoseriv.pdf
    • https://przygodanaukrainie.pl/admin/ckfinder/userfiles/files/80352892509.pdf
    • http://plechotice.sk/tmp/file/88773851226.pdf
    • https://bluetact.com/ckfinder/userfiles/files/jazepoduwefumoxuvuviroxos.pdf
    • http://naturestuff.nl/siteimages/file/14913499469.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=wheel+of+fortune+mod+apk
    • 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_off0000d7a7.bin
3d4c137cc52a17b158e61436c1abb3e9fe24a3c46ede947f5c1ac0cb1ba5566e
pdf-font-stream PDF embedded font (sfnt) at offset 0xD7A7 10688 bytes
font_01_sfnt_off0000effc.bin
2538c0ed278bae33711cbe50e3f5d8833f81c6b0b291108c31a8f753df6cbde6
pdf-font-stream PDF embedded font (sfnt) at offset 0xEFFC 19152 bytes
font_02_sfnt_off00012203.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12203 16792 bytes