Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c1ef0319f7d9fe9…

MALICIOUS

PDF

73.3 KB Created: 2021-09-06 22:45:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 727165cf27be9c926d988e3a0d8b51b0 SHA-1: 74adad04ac87f44777ab19617b56d6e6218daf96 SHA-256: 8c1ef0319f7d9fe921f02d688cc4b1298fb2146af78667629db0667d926aa7f4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with many URLs pointing to compromised WordPress sites and disposable hosting, suggesting a phishing or malware distribution scheme. Although no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of an attempt to redirect users to malicious content, likely facilitated by embedded JavaScript.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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://robinio.de/wp-content/plugins/super-forms/uploads/php/files/1qv7u72a5e6of4uieuh80sric7/63087205549.pdf In PDF document text
    • https://hsegroup.ru/wp-content/plugins/super-forms/uploads/php/files/ism2q3qbh2smc511a7hul0l350/katuxereperuju.pdfIn PDF document text
    • https://humble-brag.com/wp-content/plugins/super-forms/uploads/php/files/9a6el36s8bqsu1f4v7eumdplef/53793223259.pdfIn PDF document text
    • http://dailymaytrogiang.com/userfiles/files/bexotagabo.pdfIn PDF document text
    • http://www.marsagri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b235195d7b2---jizibutawu.pdfIn PDF document text
    • http://elateridae.com/images/FCKeditor/file/gubamuzore.pdfIn PDF document text
    • http://traditionsradio.com/wp-content/plugins/super-forms/uploads/php/files/tsis3spvs99p1otjvg1hm4j4o6/xetogogiwuluneka.pdfIn PDF document text
    • https://tekartltd.com/upload/files/wunoromenejika.pdfIn PDF document text
    • http://relaxzenter.com/uploads/files/69450902077.pdfIn PDF document text
    • http://renknh.com/ckupload/files/88884195821.pdfIn PDF document text
    • http://www.playerclub.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607d8be554e3e---48014432691.pdfIn PDF document text
    • https://stradatextiles.com/upload/ckfinder/files/gobegodatujekibe.pdfIn PDF document text
    • https://marosme.ro/hirek/file/80335896282.pdfIn PDF document text
    • https://sarujiovalente.com/wp-content/plugins/super-forms/uploads/php/files/j6lklfae15l68c6saui5c2aodg/fekovumawedorifuwa.pdfIn PDF document text
    • https://thefertilizergranulator.com/d/files/bopofixujusekuwigajopote.pdfIn PDF document text
    • http://samilove-payitforward.com/clients/f/f9/f9b0b202ed5d2cb263a89f8a9bd08a94/File/ranirevebezedipitar.pdfIn PDF document text
    • http://usmleworkout.com/files/file/wolidetinudinojaxutura.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=bengali+mystery+books+pdfPDF 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_off0000b860.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB860 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d077.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD077 11240 bytes
SHA-256: d7a97478b4cceb8b82814e2f3cf7f3ca0fd8b5ef0087f261cfeae11b73156ea7
font_02_sfnt_off0000ea6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA6A 17668 bytes
SHA-256: fc7512574cff2b57785548125478084ae4fcaf401cb12a13a1a697c330638b98