Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8437758bc918a90…

MALICIOUS

PDF

80.4 KB Created: 2021-09-09 10:08:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: cba0a94747bc8b51fa4968c359146e0a SHA-1: fcf8cb6ed7b043ef87405539d5e572b88a768312 SHA-256: a8437758bc918a902aa4fcefee6a74f589ca8e9146f055c9a65fc3fa233aea27
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample is a PDF file identified as a phishing trojan by ClamAV and a machine learning classifier. It functions as a link farm, containing numerous URLs that point to various domains, many of which are hosted on compromised CMS uploads or disposable hosting. The primary purpose appears to be directing users to external, potentially malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/161378d7e5adeb---motijafov.pdf In PDF document text
    • http://savitapiti.org/ckfinder/userfiles/files/34150638577.pdfIn PDF document text
    • https://trompis-tondschungel.de/userfiles/file/16082848446.pdfIn PDF document text
    • http://ydchem.cn/filespath/files/20210902181000.pdfIn PDF document text
    • http://ventima.ru/userfiles/file/56843553843.pdfIn PDF document text
    • http://ziepniekkalns.lv/wp-content/plugins/formcraft/file-upload/server/content/files/161359e8eb92d0---8011576340.pdfIn PDF document text
    • http://antoniolescio.net/userfiles/files/bebud.pdfIn PDF document text
    • https://cfi-registration.org/buzzboxgift/img/userfiles/files/dotupegewuxe.pdfIn PDF document text
    • https://dobre-akce.cz/media/files/file/27183771069.pdfIn PDF document text
    • http://dorapeyzaj.com/userfiles/file/devadefupuxede.pdfIn PDF document text
    • https://yastudio.net/wp-content/plugins/super-forms/uploads/php/files/2cdbae3c8ac34b7c8d16f9403b598eef/2903925358.pdfIn PDF document text
    • https://www.stnedu.com/ckfinder/upload/files/modelosemawewogozakoxir.pdfIn PDF document text
    • http://schokoladenfontaene.de/idata/riremebenoratuzav.pdfIn PDF document text
    • http://tainanrup.longi.tw/uploadfiles/files/20210903_105901_3136.pdfIn PDF document text
    • http://gowowdeli.com/uploads/files/pofasiriratodakasesisuxe.pdfIn PDF document text
    • https://euforbiabulgaria.com/uploads/pages/files/kaguwigemuvowezutud.pdfIn PDF document text
    • http://hosteleriayvending.com/ckfinder/userfiles/files/14385254752.pdfIn PDF document text
    • http://kfoodntea.com/dataroom/file/sijebasosodudozurepuvif.pdfIn PDF document text
    • http://www.florentmaussion.net/userfiles/File/ruteniluxujero.pdfIn PDF document text
    • http://jodhpurheritagewalk.com/images/file/tidoradu.pdfIn PDF document text
    • https://ikincielinmak.com/upload/ckfinder/files/17881871873.pdfIn PDF document text
    • https://chatham-ebenezer.ckdomain.com/uploads/userfiles/files/4923398515.pdfIn PDF document text
    • https://k31szmq42-nu28.com/contents/files/41610678952.pdfIn PDF document text
    • http://tichdiem.surecare.vn/uploads/userfiles/file/welufazaxanul.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=city+game+apkPDF 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_off0000d6c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6C0 10296 bytes
SHA-256: 7da63e432c3bd6eea2b64fbb46c3afc3fbf637fd7de2694a8957fd24a6ff94c6
font_01_sfnt_off0000ee07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE07 17708 bytes
SHA-256: 4fa7b7c7992bfc7eaec552780c7aac3b5098f7ad93707459c743907129fbace3
font_02_sfnt_off00011bdf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BDF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1