Malicious PDF — malware analysis report

Static analysis result for SHA-256 31a90821d0b9355f…

MALICIOUS

PDF

71.9 KB Created: 2021-09-11 21:29:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: bce1eb10d2821a440aab4ebe101a3028 SHA-1: ae95b0567faade571ad81d514a16eeac776d6dff SHA-256: 31a90821d0b9355f0d0e5a40f8d893fb1f0a5be591539c59cdc36e0b5868fb21
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The PDF contains numerous links, many pointing to compromised CMS upload storage and disposable hosting, suggesting a link farm designed to redirect users to malicious sites. While no scripts were explicitly extracted, the presence of embedded URLs and the nature of the link farm heuristics strongly suggest the document is intended to facilitate phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://bringem.de/wp-content/plugins/super-forms/uploads/php/files/adf3b0eb37177cc2472e21f8669dc46e/dezixos.pdf
    • http://tabbanbros.com/admin/fckeditor/editor/filemanager/connectors/upload/file/31686790411.pdf
    • http://sochi-polyana.com/ckfinder/userfiles/files/zodurenizeguxo.pdf
    • https://trucraftsmanship.com/wp-content/plugins/formcraft/file-upload/server/content/files/161366abc5268e---10809059322.pdf
    • http://kleiberit.ru/files/file/30120074580.pdf
    • http://astmasme.com/userData/board/file/74531644610.pdf
    • http://tortsurprise.ru/upload/redactor/files/tademigugoxupexojisuv.pdf
    • https://ozora.schaffsen.com/contents/file/84543422982.pdf
    • http://fst-uinsu.net/userfiles/files/70209851384.pdf
    • https://cullinanconstruction.com/wp-content/plugins/super-forms/uploads/php/files/9kbd7rgcp60tmjh0netv47icue/32115908734.pdf
    • http://baigeleather.com/userfiles/file/vuvizabokotetaboredomiwim.pdf
    • http://solmoda.it/userfiles/files/latilenadopesipe.pdf
    • https://autosofortkauf.ch/wp-content/plugins/super-forms/uploads/php/files/h65csgs2n364s7npbnlh6lmfc5/vimomasafodow.pdf
    • http://autosklo.sk/pictures/file/dujidebodisagupadadum.pdf
    • https://reklama71.ru/upload_picture/13565777687.pdf
    • http://tsyrulnikov.ru/upload/file/97661181630.pdf
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c023ef1965---33388698780.pdf
    • https://boumqueur-edition.com/upload/fckeditor/file/57096700386.pdf
    • https://huanghecables.com/d/files/38396701617.pdf
    • http://conblocmanado.com/pics/file/zivubilujalikuzed.pdf
    • http://boxethai38.com/upload/file/metuzuxoneredamilikoni.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=pre+intermediate+headway+student%27s+book+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_off0000b750.bin
a2617bafeedb92429d5ff355cb4d8aca52e04ea3862d7b0ea3c473787fb16099
pdf-font-stream PDF embedded font (sfnt) at offset 0xB750 11284 bytes
font_01_sfnt_off0000d183.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xD183 16792 bytes
font_02_sfnt_off0000e995.bin
e0213783d8d7a584d63e2bcdddb0ebcf80216647a6e9597fbca302dc0a6f2c21
pdf-font-stream PDF embedded font (sfnt) at offset 0xE995 15868 bytes