Malicious PDF — malware analysis report

Static analysis result for SHA-256 c135c5d130b2aa41…

MALICIOUS

PDF

81.3 KB Created: 2021-10-07 15:51:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 30738c1396b8561e725b8b53f1c21739 SHA-1: cd0d3035ec76f1e5eec5d7bf89604c466eac4b7c SHA-256: c135c5d130b2aa416cad201e165c9d3b25169dee9e5e86038fc6e13f13412dd0
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with multiple URLs pointing to compromised CMS uploads and disposable hosting. The document body was unreadable, but the presence of numerous external URIs suggests the primary purpose is to redirect users to potentially harmful websites, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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://archism.ru/uplcv?utm_term=hope+your+meeting+goes+well PDF link annotation
    • https://avflash.nl/upload/files/60596983788.pdfIn PDF document text
    • https://eurochen.com/UpFiles/WebEditorFiles/file/lekegobipopikutakatiwe.pdfIn PDF document text
    • https://brawlcall.com/ckfinder/userfiles/files/tevufeforojolim.pdfIn PDF document text
    • https://rhdplumbing.com/wp-content/plugins/super-forms/uploads/php/files/9e99b1e21859176efb532c915ff4e412/32399948007.pdfIn PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/16153bfac97f9f---dewidoguk.pdfIn PDF document text
    • http://s2ipower.com/survey/userfiles/files/pefiw.pdfIn PDF document text
    • http://fusheng-vietnam.vn/admin/webroot/upload/image/files/37225213917.pdfIn PDF document text
    • https://atlas-consulting.ro/fckeditor/fisiere/file/sozedudinopoxozud.pdfIn PDF document text
    • http://vandervalk.reviews/app/webroot/files/userfiles/files/36178404164.pdfIn PDF document text
    • http://xn--80aadq3ae7aa5k.xn--p1ai/upload/file/saduviwosikasovisuv.pdfIn PDF document text
    • http://espokebar.com/uploads/files/61074942074.pdfIn PDF document text
    • http://ktcyy.com/ckfinder/userfiles/files/dobebudo.pdfIn PDF document text
    • http://naszemotyle.natura2000.pl/imgturysta/files/sinotitazedikunasofos.pdfIn PDF document text
    • https://amzentransportationindustries.com/admin/imagetemp1/file/dimedituna.pdfIn PDF document text
    • http://ghefootmassage.com/fckeditor_userfiles/file/30211383727.pdfIn PDF document text
    • http://yyfxsw.com/upload/files/50106595783.pdfIn PDF document text
    • http://elitaliaweb.it/upload/file/bisodedinigemupigobibikus.pdfIn PDF document text
    • http://www.megasaludips.com/wp-content/plugins/formcraft/file-upload/server/content/files/161421646d053a---pizeduwategusogokuwul.pdfIn PDF document text
    • https://client-sms.com/ckfinder/userfiles/files/xujojun.pdfIn PDF document text
    • https://bestcaps99.com/ckfinder/userfiles/files/12759044684.pdfIn PDF document text
    • http://clubesquilacoma.com/uploads/files/mezevidazogurix.pdfIn PDF document text
    • https://acrgroup.nl/userfiles/file/79786378222.pdfIn PDF document text
    • http://scea.edu.mn/ckfinder/userfiles/files/jixujaja.pdfIn PDF document text
    • http://begues.mobi/userfiles/file/kilerajabesopasuzudag.pdfIn PDF document text
    • https://royal-art.pl/uploads/userfiles/files/lisisa.pdfIn 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://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_off0000d88c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD88C 10724 bytes
SHA-256: a37eb6e0d5ec1e316c5aecfa9b05a48ad89d5ac9b7f961158af933c60bd6d322
font_01_sfnt_off0000f12c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF12C 18060 bytes
SHA-256: c6ae5e252ff3c1a84724899651c1e4b8ec9828d481afd3b445645c9e70c94d50
font_02_sfnt_off00011fc8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FC8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1