Malicious PDF — malware analysis report

Static analysis result for SHA-256 f4d761c7a1be91ed…

MALICIOUS

PDF

108.0 KB Created: 2021-09-19 04:54:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 43c1dc438c6aebe7367771f00863e2a9 SHA-1: 74c7db2af0f6325c0632acf56f5ccdca35d6306b SHA-256: f4d761c7a1be91ed3b96b50bcdde9a3968db89ff37e99db8ed4d652cf43d1cd1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some hosted on compromised WordPress sites. The PDF's structure and the presence of numerous links suggest it is designed to redirect users to potentially malicious content, such as phishing pages or malware download sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9828

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://andrejc.si/files/file/4768719730.pdf In PDF document text
    • http://gorisum.net/fckeditor/upload_file/file/juxiworiw.pdfIn PDF document text
    • http://les-dvorik.ru/userfiles/file/zezelebisotuz.pdfIn PDF document text
    • http://kfnmsz.com/upfolder/e/files/20210905013041.pdfIn PDF document text
    • http://kxqcgs.net/filespath/files/20210911044330.pdfIn PDF document text
    • https://growlocals.com/wp-content/plugins/super-forms/uploads/php/files/8631fd2d1b8ade48a4604ca0c4eb3a4e/dixipek.pdfIn PDF document text
    • http://air-con.ru/upload/files/41099886434.pdfIn PDF document text
    • http://compie.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161372640d13a3---47464475309.pdfIn PDF document text
    • http://dedanskecasinoer.dk/userfiles/file/bomiregegoliduwudun.pdfIn PDF document text
    • https://www.hotelrestaurantmacarena.fr/ckfinder/userfiles/files/tudabisopazosukob.pdfIn PDF document text
    • http://balone.net/_upload/file///74582591799.pdfIn PDF document text
    • http://mirembeestate.co.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1613538a2ee406---jewarafupejobogafejore.pdfIn PDF document text
    • http://dansensvenner.dk/imagesfile///85922538124.pdfIn PDF document text
    • http://thai-apsproducts.com/file_media/file_image/file/sojejirogafeladuwi.pdfIn PDF document text
    • https://urbanshapes.in/userfiles/file/5147815481.pdfIn PDF document text
    • https://bankubezpieczen.pl/userfiles/file/soduz.pdfIn PDF document text
    • http://www.beverburcht.nl/upload/files/80327029275.pdfIn PDF document text
    • https://stiff.pl/ckfinder/userfiles/files/dakanomedutuwozujipev.pdfIn PDF document text
    • http://wenxuezj.com/images/File/90247948599.pdfIn PDF document text
    • http://dioceseofniranam.org/userfiles/file/lirewuwumeginodepekov.pdfIn PDF document text
    • https://webdatedepot.com/userfiles/file/3841058123.pdfIn PDF document text
    • http://pune-india.info/userfiles/file/wafokivixuvudiko.pdfIn PDF document text
    • http://www.arborvitae.cz/ckfinder/userfiles/files/79547080714.pdfIn PDF document text
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/161445f976a6ba---26171814467.pdfIn PDF document text
    • https://windfreeklima.com/upload/ckfinder/files/lesapozijunage.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=voa+viet+nguPDF 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010989.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10989 1936 bytes
SHA-256: 9aeb06937c81a5c56cf99af8deab830259c8e7bb488e779e8e638c33337cf583
font_01_sfnt_off0001127f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1127F 28912 bytes
SHA-256: c5d99ef2b06f393436649e0ee46ac24834077f21142482e884fdbff55d3c6fc2
font_02_sfnt_off00015aa4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15AA4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off000172b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x172B5 16720 bytes
SHA-256: 7cba0273e76654ef361ae7c6d54737e676ac24e0fccdafb3aea7b3a9a1b2cc6d
font_04_sfnt_off00018aac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18AAC 10104 bytes
SHA-256: e64f9d8d382c6276480f722cc905b0255596c2aff8c5609c9a8d0300c223e3e3