Malicious PDF — malware analysis report

Static analysis result for SHA-256 857b3efacd456a42…

MALICIOUS

PDF

70.7 KB Created: 2021-09-25 09:48:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 64fa0f45d6aedada2ca960da132929e0 SHA-1: dc843030867312f823325bea4672285d519c7145 SHA-256: 857b3efacd456a42bb55a526749fa735e0f1eb6f28536b9b6ac867c1f24389ef
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by a machine learning classifier and ClamAV, flagging it as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple disposable domains and compromised CMS upload storage. The 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 links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9849

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 http://moneymaker-gold.de/files/lefuvexudokixozapopel.pdf In PDF document text
    • https://phuketwebstudio.com/ckfinder/userfiles/files/16022443533.pdfIn PDF document text
    • http://www.goataxiservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614e823cdf11b---lavaxofeje.pdfIn PDF document text
    • http://crm333.com/documentos/file/noxogolijuwiratol.pdfIn PDF document text
    • http://safeabortionnepal.com/userfiles/file/96869652848.pdfIn PDF document text
    • http://abwvictory.com/uploads/files/vogosovigepiji.pdfIn PDF document text
    • http://weiddy.com/uploads/files/202109152200233561.pdfIn PDF document text
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614b8fb84c624---ratepekukudowatunu.pdfIn PDF document text
    • https://laptopserwis.com/app/webroot/media/files/23262295706.pdfIn PDF document text
    • https://australiancaravancentre.com.au/application/third_party/ckfinder/userfiles/files/1562757677.pdfIn PDF document text
    • https://egokituz.org/files/galeria/files/75415332403.pdfIn PDF document text
    • https://keralatemples.info/ckfinder/userfiles/files/vozobonugi.pdfIn PDF document text
    • http://powerfalcon.net/uppic/files/ropefodafetipi.pdfIn PDF document text
    • https://synodradomski.pl/userfiles/file/sesufavegubuveb.pdfIn PDF document text
    • https://gcr.goldcrownresort.com/magazine_files/files/wamife.pdfIn PDF document text
    • https://awinresource.com/uploadfile/file/xinosafaga.pdfIn PDF document text
    • https://eurotig.ro/file/18106959425.pdfIn PDF document text
    • http://odra.cycling-recycling.eu/imgturysta/files/43666866153.pdfIn PDF document text
    • https://intersat.lv/files/file/ribejibovuxojatavewufanat.pdfIn PDF document text
    • http://www.polni.si/Images/files/32851604775.pdfIn PDF document text
    • http://studiolegalezullo.eu/userfiles/files/81610911317.pdfIn PDF document text
    • https://mehreganimaging.com/images/upload/files/65187332187.pdfIn PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ee177816e5---16417303916.pdfIn PDF document text
    • http://herium.net/FileData/ckfinder/files/20210910_B44068B18BC9BD98.pdfIn PDF document text
    • http://webursitet.org/Files/file/pububefesifigojoxemefupog.pdfIn PDF document text
    • http://dungcumaymoc.com/Images_upload/files/71684508724.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=moonlight+sonata+movement+3+piano+sheet+musicPDF 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_off0000b26a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB26A 11052 bytes
SHA-256: fe434b4f56e90d2491fbb0f26d301f1af12808fbde98bdd51f6397d1abcb3668
font_01_sfnt_off0000cc06.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC06 16144 bytes
SHA-256: 2c3400aff4b8a212b5050a4f07db5a2672aa1f4091aec76a2236a0d5e698ab00
font_02_sfnt_off0000f501.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF501 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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