Malicious PDF — malware analysis report

Static analysis result for SHA-256 638daa668c940fa5…

MALICIOUS

PDF

85.2 KB Created: 2021-09-12 11:33:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 3718a77358279500a15ea49c32e20fd0 SHA-1: 099f67d479befa05d04144cf3d8e82a7f1e18183 SHA-256: 638daa668c940fa595514fc6141a51da81e1c15db16000bf469637bb92b8821b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple disposable domains, some of which are compromised WordPress uploads. The embedded URLs and the nature of the heuristics suggest an attempt to distribute malicious content or phish for credentials.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://restavratorstvo.com/ckfinder/userfiles/files/xofusuzizunenowijir.pdf In PDF document text
    • http://www.masozilina.sk/ckfinder/userfiles/files/kizupokadixivepat.pdfIn PDF document text
    • http://casms.org/atts/news-files/file/jirer.pdfIn PDF document text
    • http://gps-tw.com/CKEdit/upload/files/nokejaw.pdfIn PDF document text
    • http://svarovani-tig.cz/userfiles/file/41381680046.pdfIn PDF document text
    • https://www.cocochan.com.pk/wp-content/plugins/super-forms/uploads/php/files/59724b96a85a386d345a01f9c15bb2b0/83082600629.pdfIn PDF document text
    • http://zssadkowice.pl/pliki/donikitowigitaxipubogivef.pdfIn PDF document text
    • https://biserica-izvorul-tamaduirii.ro/files/vazorobe.pdfIn PDF document text
    • http://mastrodibaglio.it/userfiles/files/dalisarumemerewenexipebi.pdfIn PDF document text
    • http://fotografoenricogiampieri.it/userfiles/files/51453519544.pdfIn PDF document text
    • http://domusanna.it/userfiles/files/vubupivoxenofatozud.pdfIn PDF document text
    • http://chickendaylacrescenta.com/uploads/files/vonirixeweturinex.pdfIn PDF document text
    • https://sportyou.fr/ckfinder/userfiles/files/71915099778.pdfIn PDF document text
    • https://www.le-domaine-de-hauterive.fr/ckfinder/userfiles/files/20978227232.pdfIn PDF document text
    • http://thrifty-uy.com/files/others/58313583769.pdfIn PDF document text
    • http://intertribo.sk/files/4808995824.pdfIn PDF document text
    • http://www.mecateengenharia.com.br/ckfinder/userfiles/files/81177316424.pdfIn PDF document text
    • http://leasingtowers.com/ckfinder/userfiles/files/jupusedudukamige.pdfIn PDF document text
    • http://psychologadamczak.pl/userfiles/file/zokiwolamobabunof.pdfIn PDF document text
    • http://guchen.ru/d/files/68063786658.pdfIn PDF document text
    • https://letajicikoberce.cz/userfiles/file/67353738246.pdfIn PDF document text
    • https://phuquiland.com/upload/files/62509976001.pdfIn PDF document text
    • https://soosekszer.hu/upload/files/24429265828.pdfIn PDF document text
    • http://deurwater.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137e03b3b9ff---96377051769.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d4d6f83377---kimotuwadosuturaxigitaveb.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=weibo+app+apk+downloadPDF 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_off0000e156.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE156 10332 bytes
SHA-256: 05ea8038a4359b2cd25598ca5695770fc8d53b8ca55336bbfbe8a16ad5f7166d
font_01_sfnt_off0000f87e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF87E 20600 bytes
SHA-256: 36cc68a39c8b406af3944174c6476bfe63dde95219ef8165235144e10022cb72
font_02_sfnt_off00012f10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12F10 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1