Malicious PDF — malware analysis report

Static analysis result for SHA-256 a81a79d6e8c8361b…

MALICIOUS

PDF

74.5 KB Created: 2021-09-01 03:05:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 1f6b0ace906d0fcb8487d8629cf23062 SHA-1: 6430257be813114382e4a42f9b007b6eefb0871b SHA-256: a81a79d6e8c8361b100a702386495d4479388973bb837f8ab4c6652b078e26f8
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links to compromised CMS upload storage and disposable hosting, suggesting it functions as a link farm to distribute malicious content or phish users. The presence of external URIs and the nature of the heuristics point towards a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://wastran.ru/uplcv?utm_term=reciprocal+of+a+function+calculator PDF link annotation
    • http://metabolit-plus.ru/files/file/vezubexisigeduxoziva.pdfIn PDF document text
    • http://kalmi.ru/upfiles/files/74267761876.pdfIn PDF document text
    • http://lyzebrno.cz/userfiles/file/wuzumitimutomazigemix.pdfIn PDF document text
    • https://lightspec.com/wp-content/plugins/super-forms/uploads/php/files/0a0b165b61739e420340859b21cf00cf/30285220944.pdfIn PDF document text
    • http://hanarotalk.com/userfiles/file///36642641693.pdfIn PDF document text
    • https://www.frankcapassoandsons.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608799371396a---firefafudotabumirivaw.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f5dd257cee---wugetoxabawo.pdfIn PDF document text
    • http://orthopaede4you.de/userfiles/file/jalubageludafotulegegub.pdfIn PDF document text
    • https://topclassgreenery.nl/images/file/48706769655.pdfIn PDF document text
    • http://casier-a-bouteilles.fr/file/doposavuwumufovi.pdfIn PDF document text
    • https://gk-termopanel.ru/wp-content/plugins/super-forms/uploads/php/files/c5e187042f7856a7f7ec3605a2c6991c/54401259743.pdfIn PDF document text
    • https://xn--80aaijz0c.xn--p1ai/ckfinder/userfiles/files/72691356605.pdfIn PDF document text
    • https://meganimal.pt/site/upload/file/murixasonimazafubolewuti.pdfIn PDF document text
    • http://kbidc.kr/upload/editor/file/1629460909.pdfIn PDF document text
    • http://metabolitplus.ru/files/file/10674762181.pdfIn PDF document text
    • http://istanbulballoons.com/ckfinder/userfiles/files/lusumegosavolepogobafali.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c6a60566212---45017198910.pdfIn PDF document text
    • http://www.commandinglife.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ce0c97ba94---sisini.pdfIn PDF document text
    • https://paloaltospeakerseries.com/wp-content/plugins/super-forms/uploads/php/files/751c5a01656a84133ab0ac403db97c35/raforubewededakag.pdfIn PDF document text
    • https://asiastudy.in/ckfinder/userfiles/files/60960370226.pdfIn PDF document text
    • https://gauravkankariya.com/wp-content/plugins/super-forms/uploads/php/files/4ae120435efcb214d6068c1c68dd3dc6/pofegogexowevi.pdfIn PDF document text
    • https://wurstfargo.com/wp-content/plugins/super-forms/uploads/php/files/c132afabbfdb58104dfe7154cd324f3e/36770187763.pdfIn PDF document text
    • https://vaitinhdien.com/app/webroot/upload/files/45446000149.pdfIn PDF document text
    • https://www.webhisto.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160bca8cd73152---55803112140.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_off0000bd88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBD88 10448 bytes
SHA-256: 5a83e236e9bd42211f151aba10bea9c941a8e32300b6f4dd6bbec1b9845aa097
font_01_sfnt_off0000d553.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD553 18092 bytes
SHA-256: 5b481428ccc6e2da2ace4463edb16896473110d3d23f4e0b2c2a87dd3db90e44
font_02_sfnt_off000104ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104AB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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