Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c73e36fc356ac6f…

MALICIOUS

PDF

102.4 KB Created: 2021-09-06 19:44:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 4aa5a85f9b0554466a77c03657b19545 SHA-1: ac0f0aa5b87656bf6986b749b36ec7f509c81aa8 SHA-256: 8c73e36fc356ac6f24edef7bb28c16bbae7722497faf6f3c2f2e32beb4789dcd
176 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It functions as a link farm, directing users to numerous compromised WordPress upload storage locations and other potentially malicious domains. The presence of multiple distinct hosts and the use of 'utm_term' parameters suggest an attempt to manipulate search engine results or disguise the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9909

Heuristics 7

  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://mas.vacations/wp-content/plugins/formcraft/file-upload/server/content/files/1607c9cacbf8f1---woxarovagipefinozasova.pdf In PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/kavq5no61uj76t1k0lj8ui98m8/88980653339.pdfIn PDF document text
    • https://rosedreamholidayhomes.com/ckfinder/userfiles/files/mafuz.pdfIn PDF document text
    • http://www.hollyskauaicondo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160820d0ab5aa2---balanikuku.pdfIn PDF document text
    • https://www.golddustdental.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608440efe83be---18690150224.pdfIn PDF document text
    • http://habitat3.eu/userfiles/files/99058950693.pdfIn PDF document text
    • https://mimpishio1bet.com/contents//files/jopopew.pdfIn PDF document text
    • http://wchs65.org/clients/b/bb/bb65574a37642f7fe3135935df861e67/File/97812788333.pdfIn PDF document text
    • http://abwmercury.com/uploads/files/zivaforigibinuzozenu.pdfIn PDF document text
    • http://hnfhdc.com/UpLoadFile/2021090611533478419.pdfIn PDF document text
    • https://www.swx.global/wp-content/plugins/super-forms/uploads/php/files/b04ad1157df221adfb34a10358d186d7/67527870694.pdfIn PDF document text
    • http://servicedental.it/userfiles/files/laferudef.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab312395a58---98222385443.pdfIn PDF document text
    • http://brothersaluminium.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/160c9839d7ee85---2575744603.pdfIn PDF document text
    • https://cakenflowersonline.com/userfiles/file/futowuridori.pdfIn PDF document text
    • http://www.kevinbrooks.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160841d87b0e44---86696110364.pdfIn PDF document text
    • https://medgarlci.com/wp-content/plugins/super-forms/uploads/php/files/3bdcae595434ff8292f3fb4206db8fab/89266367209.pdfIn PDF document text
    • https://4appsoftware.it/file/65301302959.pdfIn PDF document text
    • https://www.ideaklinikankara.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071e81ce5b63---kogazejofa.pdfIn PDF document text
    • http://gustosandvic.com/ckfinder/userfiles/files/vawoxujegusexobufabamot.pdfIn PDF document text
    • https://noukos.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1609b26ff96f5b---xafag.pdfIn PDF document text
    • https://www.okcfarmersmarket.com/wp-content/plugins/super-forms/uploads/php/files/ede223e659102d2c0ffc222339130faa/73592004019.pdfIn PDF document text
    • https://hattoco.vn/images/ckeditor/files/28291346926.pdfIn PDF document text
    • http://stroynerud-sm.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161265ab1989fc---20146279484.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=alcatel+u3+4g+manualPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010b6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B6B 17544 bytes
SHA-256: 69a93a4441d44d3d024cd58ab6708a1c9b217cf7a1c515453acd84b418a00463
font_01_sfnt_off00012646.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12646 19588 bytes
SHA-256: 1871e0bae63183365a172feb1d1299862bcd147f2224a23c7f37d000a8530809
font_02_sfnt_off00015a15.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15A15 10424 bytes
SHA-256: 0bbc228467165400d643d4d6cb5516da6a802435a14f14a0a512f468b9d194d5
font_03_sfnt_off000171d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x171D9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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