Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8d70c7e328fe176…

MALICIOUS

PDF

76.0 KB Created: 2021-09-29 06:00:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8552bf4c0ad83419a5e6ec9d35929059 SHA-1: 2954e0f857bb3c2ea9879ac5f46a03a38744014b SHA-256: c8d70c7e328fe176634b7b94d597da3b51b7db705c2ecb5a97c4e29b5bf0a288
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple heuristics indicating it's a link farm hosted on compromised WordPress sites and disposable domains, designed to lead users to malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely for phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and URL patterns are typical of documents that redirect users to exploit kits or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9901

Heuristics 7

  • 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 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.
  • 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://ryukatsu.com/userData/board/file/18156315343.pdf
    • http://augustaelectricalwork.com/editorData/file/36928183276.pdf
    • http://101balkon.ru/upload/files/zinuwerijamaboradajidup.pdf
    • https://homestayhoian.vn/uploads/image/files/nazetowuzivotozebek.pdf
    • http://pegastelco.com/pictures/files/68132357355.pdf
    • https://profipreklady.cz/www/ckfinder/userfiles/files/76562905888.pdf
    • https://www.capitalroofingct.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613329499ba88---43260546894.pdf
    • http://coachhouse.info/assets/file/63160727856.pdf
    • http://massimosusto.eu/userfiles/files/54050816453.pdf
    • http://olivetheater.com/userData/board/file/26034987004.pdf
    • https://hearing-outlet.com/uploads/files/202109030453533689.pdf
    • https://markmont.eu/editor_uploads/system/files/62979460818.pdf
    • https://tainandentist.com/uploads/files/202109090749008663.pdf
    • http://ketoanaca.com/uploads/image/files/74270099371.pdf
    • http://thy-environment.com/userfiles/files/58221949154.pdf
    • http://gojjang.com/uploads/files/wukagegebukazabot.pdf
    • http://jubileejec.com/userfiles/files/33584583494.pdf
    • https://amagi.la/wp-content/plugins/formcraft/file-upload/server/content/files/1613df0ff3d82f---xozim.pdf
    • https://ctapigroup3.com/contents/files/41369822247.pdf
    • http://evo-models.com/uploads/userfiles/files/72816192671.pdf
    • http://donghozibistore.com/luutru/files/32747045983.pdf
    • http://icsbc.ru/fuploader/file/sogulomezon.pdf
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/kr5726tdb0b16q14ul8sbf61t5/4243392602.pdf
    • https://holcom-wd.holcom.vn/webroot/img/files/nopavenoxuteworiwafave.pdf
    • https://ww150003.linebot.net/upfile/files/20210912065923.pdf
    • https://oklogistic.lv/upload/file/76589571193.pdf
    • http://caycanh.vn/images/fck/file/25927933018.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=catalogo+fraiche+2018+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_off0000be0f.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xBE0F 16792 bytes
font_01_sfnt_off0000d621.bin
a3c0c59d5a05e3da9dbe6f54c9625c1aec7e2b361a76796debc702261c49456d
pdf-font-stream PDF embedded font (sfnt) at offset 0xD621 19000 bytes
font_02_sfnt_off000107aa.bin
905b4d4438b0ac911e3220c97340d68ce4cb2cab60f9ac2cb2d3fae67ff70a4a
pdf-font-stream PDF embedded font (sfnt) at offset 0x107AA 11160 bytes