Malicious PDF — malware analysis report

Static analysis result for SHA-256 900aa86992296b45…

MALICIOUS

PDF

80.3 KB Created: 2021-06-11 03:15:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: ab255b5bf62f0ebff647c38791404a63 SHA-1: 53d542821b33fbbe8eb5d716e712670a302c48f6 SHA-256: 900aa86992296b45669ec5b77567c923e20e97bf26779d661e6459cad4488656
156 Risk Score

Malware Insights

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

The PDF document contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. The document body, though heavily obfuscated, contains metadata related to wkhtmltopdf and date/time information, but no direct user-facing text that would indicate a specific lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 https://smidgel.ru/uplcv?utm_term=three+properties+of+alkaline+earth+metals PDF link annotation
    • http://opakowania-loga.pl/zdjecia/fotki/file/33879104853.pdfIn PDF document text
    • https://cottonweb.net/userfiles/file/96996959653.pdfIn PDF document text
    • http://juniorsmagazine.com/wp-content/plugins/formcraft/file-upload/server/content/files/160894201b6bd5---8562441902.pdfIn PDF document text
    • http://modnyi-buket.ru/uploads/files/surutotokegabotedigodami.pdfIn PDF document text
    • https://udachi.co.th/wp-content/plugins/super-forms/uploads/php/files/l610rf124tlb7n2c18ee72m8ie/kufubagubukurodiberokowe.pdfIn PDF document text
    • https://salvatoredivilio.it/userfiles/file/nezarezotukudosuvob.pdfIn PDF document text
    • http://miamiwars.pl/wp-content/plugins/super-forms/uploads/php/files/1a6b6fa942e16ca6f86f1cfa36a9c14a/78130731414.pdfIn PDF document text
    • https://www.taxiserviceh24.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b4c5a864320---wasunabafopujuz.pdfIn PDF document text
    • https://www.chesapeake-lighting.com/wp-content/plugins/super-forms/uploads/php/files/694af7335f4ae400cbd871b0c4f85815/dudumusutamoboko.pdfIn PDF document text
    • https://vegan-eshop.cz/data/file/mezafekamoje.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-5-21/20210521191016901585.pdfIn PDF document text
    • http://ayurveda-shiatsu-nice.com/upload/files/15816168710.pdfIn PDF document text
    • https://celovechurch.org/wp-content/plugins/super-forms/uploads/php/files/6ede1dc2b02f272de0d6e2ed9b56a4c8/vifowizovipulefewip.pdfIn PDF document text
    • https://shared401k.com/wp-content/plugins/super-forms/uploads/php/files/7882669ca6779a7b3df6ef3f7f40711f/gikuwot.pdfIn PDF document text
    • https://scheidungsrecht-best.de/userfiles/file/62887613877.pdfIn PDF document text
    • http://fortlauderdalelimorental.net/wp-content/plugins/formcraft/file-upload/server/content/files/1607ba3033c808---15460211424.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000efba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFBA 4940 bytes
SHA-256: c2dd443f64691889c3e3c74737de9fad355c1ea5055dc229d44f7a7cb2174577
font_01_sfnt_off00010045.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10045 11036 bytes
SHA-256: 9fc757c742b66f2e1ea94d09bccc699e498ce0b097c45500311f88e74b29f3eb
font_02_sfnt_off000125fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125FB 4324 bytes
SHA-256: 7f6049e5011acf0e8581793f2bc2bb947aac2929fdb77abc318b2a6155c1ef71