Malicious PDF — malware analysis report

Static analysis result for SHA-256 991cd631e61bcd02…

MALICIOUS

PDF

70.3 KB Created: 2021-09-28 11:35:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 4fcadb03a308cd1f5eb432bb14826532 SHA-1: ea6d3c08f84918cc886c4335c02aa9e28122f9c3 SHA-256: 991cd631e61bcd0206356a291b3bffa01eb258a116607845101827dcd89a4b1a
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains an embedded JavaScript stream and numerous external URIs, many of which are identified as part of a link farm hosted on potentially compromised or disposable domains. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or malware delivery through these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9986

Heuristics 7

  • 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.
  • 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 https://crewmak.ru/uplcv?utm_term=clean+master+real PDF link annotation
    • http://police8coop.com/UserFiles/file/sevozutijatuwok.pdfIn PDF document text
    • https://ikitellirezistans.com/upload/files/vikujufi.pdfIn PDF document text
    • https://walnutcreekguide.com/wysiwygfiles/file/reginokizorasakesapij.pdfIn PDF document text
    • https://mbamantra.com/ci/userfiles/files/vafimemikazenorununenup.pdfIn PDF document text
    • http://chinahongji.com/d/files/julax.pdfIn PDF document text
    • https://www.tulsarad.com/my_content/js/ckfinder/userfiles/files/34553650256.pdfIn PDF document text
    • http://sofia-es.tokyo/yamituki-n/uploads/files/duxurovizupurajosi.pdfIn PDF document text
    • http://fullcolorspandoeken.nl/userfiles/file/kuxibuwibiketelozo.pdfIn PDF document text
    • http://kovacsoltvaskerites.hu/images/file/kutotat.pdfIn PDF document text
    • http://beta-rc.com/upload/files/75841227191.pdfIn PDF document text
    • http://pincesorvarshop.hu/editor_up/zolomaxag.pdfIn PDF document text
    • https://marlschuz.com/userfiles/files/xelanuxod.pdfIn PDF document text
    • https://shturnev.com/files/foFKED/file/vatijodolanarij.pdfIn PDF document text
    • http://dreiseengrundschule.de/files/25195054157.pdfIn PDF document text
    • http://dabien.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/161375255b706a---loxupadarijaxutedizetitux.pdfIn PDF document text
    • http://nexxosrealty.com/userfiles/files/41727095028.pdfIn PDF document text
    • https://faresaldabbous.com/uploads/file/19502154283.pdfIn PDF document text
    • https://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/6240d476713b304c32fc5f42cd7e09cd/35346264234.pdfIn PDF document text
    • http://kayapaliinsaat.net/file/leriwetikoxupido.pdfIn PDF document text
    • http://coca-colalife.eu/userfiles/file/wenatozixiwiv.pdfIn PDF document text
    • http://becro-plast.hr/wp-content/plugins/formcraft/file-upload/server/content/files/1613b2f6d208bd---87683149807.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_off0000b108.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB108 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c91a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC91A 17236 bytes
SHA-256: f8cee663377844f5bebc3c77f7bf7d7488ee20306ef2218a0d11c6929317dad6
font_02_sfnt_off0000f576.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF576 10088 bytes
SHA-256: f3c47f7fad47757ab68689698bdb304e77850e4a7a81827a715a23768169b862