Malicious PDF — malware analysis report

Static analysis result for SHA-256 21bb4c70fdf2e3f7…

MALICIOUS

PDF

83.3 KB Created: 2021-06-16 23:09:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 3ae79c4dd177edd1a6980881eaa9e371 SHA-1: 36af25a778b895e69a483c878838c1a36b037b29 SHA-256: 21bb4c70fdf2e3f78bf552a47dac0d1fc6ae5b4a11bf6a7a6ed96c5e0d33a874
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains numerous links to external websites, many hosted on compromised WordPress sites, suggesting a phishing or malware distribution campaign. The document body, though heavily obfuscated, contains keywords related to technical terms, likely intended to attract unsuspecting users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://nomylo.ru/uplcv?utm_term=encoder+decoder+multiplexer+demultiplexer+pdf PDF link annotation
    • http://cheers-gifts.com/userfiles/2593640195.pdfIn PDF document text
    • http://adoriantarla.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160792a912de88---waforunulubisavesixir.pdfIn PDF document text
    • https://amenajarisiconstructii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16088ffa3760a4---51269874906.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ec9901812e.pdfIn PDF document text
    • http://in-dapt.com/wp-content/plugins/formcraft/file-upload/server/content/files/160865b5f0af89---tizirunanosasu.pdfIn PDF document text
    • http://metzpaintings.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c41442e4f2---95019337892.pdfIn PDF document text
    • http://kovacsoltvaskerites.hu/images/file/wukesagevixuvawodato.pdfIn PDF document text
    • https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/2hr539uf99a16lpmo22o8rhfj2/robuve.pdfIn PDF document text
    • http://akcjonariusz.com/UserFiles/file/51107236811.pdfIn PDF document text
    • http://www.onegelha.com/wp-content/plugins/super-forms/uploads/php/files/498ce9d582e2f9e67429cb22d91c6b97/zovikopigufube.pdfIn PDF document text
    • https://advancedcheckcashadvance.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f02ab6e79e---gupijosigofijexakofulu.pdfIn PDF document text
    • https://sipare.com.ar/wp-content/plugins/super-forms/uploads/php/files/4m7npsqsvo820000fdufi8th34/19604255979.pdfIn PDF document text
    • http://dambi.pl/userfiles/file/wamewumokixilezegu.pdfIn PDF document text
    • https://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/65a5f040051489f84dc745f7a55bf82c/gulikakuguwupotesimati.pdfIn PDF document text
    • http://ghioroiu.ro/sites/default/files/file/9586481971.pdfIn PDF document text
    • http://www.lauricedale.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160850a41eeb6f---95064361431.pdfIn PDF document text
    • http://www.opentle.orgIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://www.gnu.org/licenses/gpl.htmlIn PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off0000f07f.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0xF07F 14644 bytes
SHA-256: 5af0fc97b8275ed74ff8ea646f9b0f634fc7cb3e80c2cb73b8955a567c79283a
font_00_sfnt_off0000dfc6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFC6 4940 bytes
SHA-256: 4aa5783eb391c8308b371c0a43d7500c563a43b9a30e219e356de397c86f1e70
font_02_sfnt_off00011924.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11924 10256 bytes
SHA-256: f81502f7cae66c0d6a9f073778e84f12235277177e8b39674e898aa3c1b0c478