Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf574065642b49bc…

MALICIOUS

PDF

76.3 KB Created: 2021-09-26 20:29:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 478e0ac0bb0fba876b5e2a74a120bea0 SHA-1: 74c078220ff988e14b5546c0d86e025d74b86725 SHA-256: cf574065642b49bc142438d0715509697b8bef3c456a2b8ae5ca5e84f9ccab1a
156 Risk Score

Malware Insights

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

The sample was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with multiple URLs pointing to potentially compromised or disposable hosting sites. The PDF document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://levotst.com/uploads/files/gokafenob.pdf In PDF document text
    • https://china-glass-mosaic.vegner.com/userfiles/files/20210910_191108.pdfIn PDF document text
    • https://swiz.eu/files/editor/xenidegobituganoneleg.pdfIn PDF document text
    • http://online-cycling.com/files/file/zajajinigukibolakat.pdfIn PDF document text
    • https://ncsccalgary.com/userfiles/files/91184073709.pdfIn PDF document text
    • https://hps-gruppe.com/wp-content/plugins/super-forms/uploads/php/files/4rjtgl1n2ud3cl9nvu29b2veft/73032608972.pdfIn PDF document text
    • https://www.dentaltaxpros.com/wp-content/plugins/super-forms/uploads/php/files/45aee6437e3058c98681a83db10680c3/82173701334.pdfIn PDF document text
    • http://wernitznigg.at/files/xigatusaberaxadeb.pdfIn PDF document text
    • https://harkakotony.hu/UserFiles/file/firopalawos.pdfIn PDF document text
    • http://haozuowenwang.com/imagefiles/file/rovusojanavitux.pdfIn PDF document text
    • https://bindazzled.com.au/wp-content/plugins/super-forms/uploads/php/files/1c5aaa1c7c648368fda1a824e8667165/noxunezasetexuk.pdfIn PDF document text
    • http://iscyber.com/userfiles/files/sebesedab.pdfIn PDF document text
    • https://juniorclublivorno.com/sitonews/images_upload/files/lufemoku.pdfIn PDF document text
    • http://bytip.net/filespath/files/20210906013520.pdfIn PDF document text
    • http://antwerp-rentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130c0be3f87c---dorunodabosora.pdfIn PDF document text
    • https://suacuacuontoanphat.com/upload/files/lefij.pdfIn PDF document text
    • http://dailitara.lt/bites/uploads/file/rorawopokizabuxeti.pdfIn PDF document text
    • http://geologocarmignani.com/userfiles/files/76184070763.pdfIn PDF document text
    • https://almuhja.ps/ckfinder/userfiles/files/15876872535.pdfIn PDF document text
    • http://reklama-v-sochi.com/ckfinder/userfiles/files/dabanufenubenera.pdfIn PDF document text
    • http://jujucuisine.com/userfiles/file/jowopotaxenudixuwuxo.pdfIn PDF document text
    • http://nowator-zpu.pl/userfiles/file/tividuwulalesezo.pdfIn PDF document text
    • https://foodsafebox.com/ckfinder/userfiles/files/75300081780.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=chat+app+source+code+android+studioPDF 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_off0000bc66.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBC66 10696 bytes
SHA-256: 2617aec61923d3fabe82351399ba95733731d645169abab98d6a2faf242d5df1
font_01_sfnt_off0000d4e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4E7 20608 bytes
SHA-256: a05fee482597275af629ac472af0dc24c7c249c24bafcf3d5afd4e9039c1155f
font_02_sfnt_off00010b45.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B45 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1