Malicious PDF — malware analysis report

Static analysis result for SHA-256 52ad1877166e54ac…

MALICIOUS

PDF

81.5 KB Created: 2021-09-03 21:26:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 53777eb3cd0813fb67c16580ca1f57fc SHA-1: 0a321d3a31d75f8eddf9d91588f75f235794bfa8 SHA-256: 52ad1877166e54acecb744c423051cb9a12301c31d375be7491607c1f047e34c
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external URIs and links to compromised CMS uploads, indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. The presence of embedded URLs and the nature of the links point towards a spearphishing attachment as the initial attack vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

Heuristics 6

  • 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 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://medvor.ru/uplcv?utm_term=free+following+directions+worksheets PDF link annotation
    • http://anandamsanyal.com/userfiles/file/vesit.pdfIn PDF document text
    • http://ghalemdi.com/userfiles/file/petakuji.pdfIn PDF document text
    • https://www.aironface.com/wp-content/plugins/super-forms/uploads/php/files/55212b730f1088bae5e36ed11c75d35c/puxexitunafikujax.pdfIn PDF document text
    • http://afgventuregroup.com/cfiles/file/94256517243.pdfIn PDF document text
    • http://ippinnudon.com/uploads/files/funelezinudu.pdfIn PDF document text
    • https://sharmtocairo.com/userfiles/files/84395867821.pdfIn PDF document text
    • http://kieryk.pl/img/userfiles/file/xogubilo.pdfIn PDF document text
    • https://www.caesarstravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f8938da98c---43473379170.pdfIn PDF document text
    • http://minerva-collection.net/files/files/49524611695.pdfIn PDF document text
    • https://purpleleafestatebuyers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072bc24b0cbe---42906060115.pdfIn PDF document text
    • https://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/246ded79a530aa4faefec95a711be87b/88026417044.pdfIn PDF document text
    • http://e-photo.lv/ckfinder/userfiles/files/xunosivir.pdfIn PDF document text
    • http://www.expo-hotel.com/english/wp-content/plugins/formcraft/file-upload/server/content/files/1609958f9ebd05---93607322691.pdfIn PDF document text
    • http://micronforgacsolo.hu/UserFiles/file/84261735049.pdfIn PDF document text
    • https://egca.fr/userfiles/file/safomavamabitezimalun.pdfIn PDF document text
    • https://www.treehousecare.org/wp-content/plugins/formcraft/file-upload/server/content/files/160738428ab3f7---fusuwisunoxabotaja.pdfIn PDF document text
    • http://goldenpeak.it/userfiles/files/69704067565.pdfIn PDF document text
    • https://global-brand.net/userfiles/files/fetanopan.pdfIn PDF document text
    • https://rmduncanrealty.com/userfiles/files/vasijakasuzefoxi.pdfIn PDF document text
    • http://inannamsao.com/uploads/files/12222528013.pdfIn PDF document text
    • https://bobecoingatlan.com/uploads/editor/file/wenifamepiribisisunow.pdfIn PDF document text
    • http://thaihotelsale.com/FileData/ckfinder/files/20210616_468518CF2441C69C.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_off0000da21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA21 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f233.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF233 17788 bytes
SHA-256: a1bb18f4b5c86200181bc5e5d9ac7a40d55138c4abb6ea663c36af9b12311191
font_02_sfnt_off00012000.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12000 10748 bytes
SHA-256: cf715b7c43966675382b4b068bc379d7033a4d1b413b64f42ff4cc8709ec3892