Malicious PDF — malware analysis report

Static analysis result for SHA-256 31edd5787528553b…

MALICIOUS

PDF

89.3 KB Created: 2021-07-10 11:01:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 60584bdf79bf4582a45ff86d46c9ea8c SHA-1: 4a5d8681f578fe8d932e53d4368fee512469df96 SHA-256: 31edd5787528553b413fcd18810caf62c498354a5da65630b87244e2c59ed1ec
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, indicating a phishing or trojan threat. It functions as a link farm, with numerous URLs pointing to compromised CMS upload directories, likely intended to host and distribute further malicious payloads. The document body is heavily obfuscated and contains no readable content, suggesting its primary purpose is to facilitate the download of malicious files via the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9937

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 http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ff0000fcea---goxokumukade.pdf In PDF document text
    • http://dungcubepgiangtrinh.com/webroot/img/files/48255954462.pdfIn PDF document text
    • http://xn--vb0b83rba554gca.kr/page_data/file/20210613163537.pdfIn PDF document text
    • http://studioarchperissinotto.eu/userfiles/files/viwileviketuwemasuxedoba.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5cfeb71fef.pdfIn PDF document text
    • http://lawngo.net/fckfiles/19058490928.pdfIn PDF document text
    • http://landia-print.com/pdir/file/81456493778.pdfIn PDF document text
    • https://cffcommunications.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1/160dbf1b65905d---fokene.pdfIn PDF document text
    • http://denda.co.kr/ckfinder/userfiles/files/85647098001.pdfIn PDF document text
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae4dd240591---53074197238.pdfIn PDF document text
    • https://asset-books.com/userfiles/file/13677339557.pdfIn PDF document text
    • http://jsushibrea.com/uploads/files/ruxumexitifaguxakad.pdfIn PDF document text
    • http://flightshop.jp/images/blog//file/57250657677.pdfIn PDF document text
    • https://www.costaverde.it/wp-content/plugins/formcraft/file-upload/server/content/files/16071afcc7caa1---18871975198.pdfIn PDF document text
    • https://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/7aef789a4b66580c8f7c94944403d6c2/sawolizubuselasinopajuriz.pdfIn PDF document text
    • https://iwistw.com/upload/files/fixumagubigipegalepe.pdfIn PDF document text
    • http://lushexperiences.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e21a1980da---koturadata.pdfIn PDF document text
    • https://glasschneider.koeln/wp-content/plugins/super-forms/uploads/php/files/mvh9aura7od0u7i6sfvdiff48e/62979386340.pdfIn PDF document text
    • https://akproauto.net/nbloom/fckuploads/file/fokozokumavoxapage.pdfIn PDF document text
    • https://alice-immo.com/userfiles/file/28451642890.pdfIn PDF document text
    • http://studiotravenzolo.it/userfiles/files/42603685123.pdfIn PDF document text
    • https://morethancleaningservices.com/wp-content/plugins/super-forms/uploads/php/files/36c403dd3427ddb1f1c23b1f7fc62e9b/27636246555.pdfIn PDF document text
    • http://acpiindia.com/userfiles/file/wemumavisidojixu.pdfIn PDF document text
    • https://mkting.com.co/wp-content/plugins/super-forms/uploads/php/files/7ea7a76b6ec4d56889c7bca3de6d2505/tusovapanaxuguzikekuje.pdfIn PDF document text
    • https://werbemittelag.ch/userfiles/files/89949659721.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=what+does+pdf+stand+forPDF link annotation
    • 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_off0000fbd3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBD3 16956 bytes
SHA-256: 726efb55ec2ad7076835d55a5b037a2889486f19dcd60c2df0033b989b5632c2
font_01_sfnt_off00012817.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12817 10452 bytes
SHA-256: ca80803a061d2b2a6c966a213c672a9eef58db8eb31fd202f79c6c5763e21d4e
font_02_sfnt_off00013fc9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13FC9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1