Malicious PDF — malware analysis report

Static analysis result for SHA-256 8536ddd31bf2c98e…

MALICIOUS

PDF

79.5 KB Created: 2021-09-07 02:53:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: bc5180d99401d3caa8426d7c2dc89d7d SHA-1: 914dafd93aeb7cd004803cced2d6ed4cff619de6 SHA-256: 8536ddd31bf2c98e5c64e9698c1f1515cb7559406242b10d13b9ee1447ce4eac
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. It contains numerous external URIs and links to websites, some hosted on compromised CMS platforms, suggesting a phishing or malware distribution scheme. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but likely serving as a lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://crysiq.ru/uplcv?utm_term=swagelok+valves+catalog+pdf PDF link annotation
    • http://areawifi.com/DESARROLLO/userfiles/files/2446337337.pdfIn PDF document text
    • http://marcus-1.com/FileData/ckfinder/files/20210907_DAEA0AC6AC7192A5.pdfIn PDF document text
    • http://aranykoronakft.hu/userfiles/file/lipovetu.pdfIn PDF document text
    • http://plusbateria.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b32c6d3366---fituzumiranetopajiwutiz.pdfIn PDF document text
    • http://dolphinegypt.net/userfiles/file/45452180149.pdfIn PDF document text
    • http://bjerkelunden.org/content/files/userfiles/file///95375299507.pdfIn PDF document text
    • https://plewmal-d.com/Uploads/files/dexiziderebuxokok.pdfIn PDF document text
    • http://linkingpeople.info/userfiles/file/56708933842.pdfIn PDF document text
    • http://ride-on-earth.com/images/blog/file/79446774140.pdfIn PDF document text
    • http://ks4073.com/file_media/file_image/file/zomanuxi.pdfIn PDF document text
    • http://artin-intranet.com/ckupload/files/didajadutobifemeven.pdfIn PDF document text
    • http://daming-school.com/userfiles/file/46243041747.pdfIn PDF document text
    • http://littlefreddieking.com/clients/65037/File/budagitewunelo.pdfIn PDF document text
    • https://www.tonygssoulfood.com/wp-content/plugins/super-forms/uploads/php/files/4d36772ef0462699cd174068ad9bb858/dixarugufalexadilez.pdfIn PDF document text
    • https://mannerfeltdesignteam.se/ckfinder/userfiles/files/12945807496.pdfIn PDF document text
    • https://yidinfo.net/wp-content/plugins/super-forms/uploads/php/files/ebonfdhmb4qq99qa05ffpl47ua/23174641791.pdfIn PDF document text
    • http://ktcyy.com/ckfinder/userfiles/files/ladojamaxavibuvag.pdfIn PDF document text
    • http://pmdrecycling.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606eb6a5258f7---kibafa.pdfIn PDF document text
    • https://linker.tw/files/96707911623.pdfIn PDF document text
    • http://ladyqueen.it/userfiles/files/39171478819.pdfIn PDF document text
    • http://studiodugnani.it/userfiles/files/tobunil.pdfIn PDF document text
    • 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_off0000d36f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD36F 17000 bytes
SHA-256: 4d19e6d96d31d9d2435ac9add1f04fa39fa36616b384d60d2d1b447f2447de09
font_01_sfnt_off0000ff44.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF44 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001175b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1175B 10816 bytes
SHA-256: 86b8ecaa14b26cf05b1d9026312544a4b1a876f8ca900a8e791d0ef448e06fc1