Malicious PDF — malware analysis report

Static analysis result for SHA-256 6a5e60114fa9f31f…

MALICIOUS

PDF

76.2 KB Created: 2021-09-16 07:24:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: d36bb42086ce20974cb85dce3672a1d1 SHA-1: 74f25f37e5fdff341fffe00cb9c12a86dc35bbff SHA-256: 6a5e60114fa9f31f514565312e625e0f366b0e6f3344b9196c20956b0b7ad1cb
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links, many pointing to compromised WordPress sites or disposable hosting, suggesting it functions as a link farm to distribute further malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather as a container for these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://koala-al.com/d/files/84543249633.pdf In PDF document text
    • http://zhihepvb.com/upload/ckimg/files/202109161022339520.pdfIn PDF document text
    • http://geoass.eu/userfiles/files/xikopokuxirosozajuwu.pdfIn PDF document text
    • https://equalitas.es/userfiles/file/56534095428.pdfIn PDF document text
    • http://ascensionchina.com/userfiles/file/kewunugolajuvukajoxava.pdfIn PDF document text
    • http://igs.compcierge-asia.com/ckfinder/userfiles/files/55142741310.pdfIn PDF document text
    • https://stomatoloska-ordinacija-rijeka.com/files/61075280176.pdfIn PDF document text
    • http://www.tsssport.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140211f4a684---vawekiw.pdfIn PDF document text
    • http://ecohouse-lab.com/userfiles/file/puwajebugazipivipipo.pdfIn PDF document text
    • http://qualityfirstservices.pro/testingsites/advantage_aviation/assets/media/file/bogajuduvaninud.pdfIn PDF document text
    • http://auburn-companies.com/userfiles/files/wumitufexaxekatebol.pdfIn PDF document text
    • http://chongros.com/userData/board/file/89272927854.pdfIn PDF document text
    • http://mellorymotors.ru/admin/ckfinder/userfiles/files/jexexotagipol.pdfIn PDF document text
    • http://shethof.ch/cgi-bin/dynamisch/file/30232687605.pdfIn PDF document text
    • https://faresaldabbous.com/uploads/files/59207584489.pdfIn PDF document text
    • https://www.hospedeagora.com.br/wp-content/plugins/super-forms/uploads/php/files/vhkimo4ghesk912jevsofbm01n/jigox.pdfIn PDF document text
    • https://ecohort.com/userfiles/files/37979547403.pdfIn PDF document text
    • http://salonlomi.pl/wp-content/plugins/formcraft/file-upload/server/content/files/161371dffc797f---musizuranipipigevudur.pdfIn PDF document text
    • https://keongracun.org/contents/files/wurekej.pdfIn PDF document text
    • http://jingkangchem.com/upload/files/zopasilixam.pdfIn PDF document text
    • http://sd-admin.fazendapenaazul.com/ckeditor/uploads/files/xemokukurovematon.pdfIn PDF document text
    • https://pianotuningdarwin.com/userfiles/files/97008768534.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=s21+compare+modelsPDF 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_off0000c1ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC1EA 18616 bytes
SHA-256: 3f4690cece536f6882f1eefa47dd04eefaf81e934787681e8bb69271ef9a350b
font_01_sfnt_off0000f2ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2FF 10628 bytes
SHA-256: a60b5738696e2191f12d65e3ab282f239079f09bcc16c4cc7dd29ab023774953
font_02_sfnt_off00010b5c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B5C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1