Malicious PDF — malware analysis report

Static analysis result for SHA-256 1d5527b9d5585f2d…

MALICIOUS

PDF

75.7 KB Created: 2021-09-23 15:49:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 23b08289757700b8e8f0089f23e43f30 SHA-1: 7291c9a52d45623f85e275033a486c95193a1456 SHA-256: 1d5527b9d5585f2db36e0883122d6bce2ee509f310ec4144feed9d51eaa3f533
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple distinct hosts, some of which are compromised CMS uploads or disposable domains. The embedded URLs suggest an attempt to redirect users to potentially malicious content, aligning with phishing or malware distribution tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9827

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://master-stroi76.ru/userfiles/file/11027823888.pdf In PDF document text
    • http://teraval.cz/res/file/72007646661.pdfIn PDF document text
    • http://le-bouquet.be/userfiles/files/jaxadagimen.pdfIn PDF document text
    • http://ontheedgeofnow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161481439859e1---58350220769.pdfIn PDF document text
    • http://ttlh.vn/storage/ckfinder/files/16486864806.pdfIn PDF document text
    • http://njbeihang.com/uploadfile/file///2021091314171996.pdfIn PDF document text
    • http://bienbao.org/uploads/files/52496923238.pdfIn PDF document text
    • https://holycrosshealthcare.com/userfiles/files/muzax.pdfIn PDF document text
    • https://sabagdasarov.ru/upload/file/kozafotiwome.pdfIn PDF document text
    • http://viorina-deko.com/images/file/33385257151.pdfIn PDF document text
    • https://gitteszoneklinik.dk/ckfinder/userfiles/files/ragokugixape.pdfIn PDF document text
    • http://koryosushi.com/uploads/files/54610322797.pdfIn PDF document text
    • https://castilloexterior.net/ckfinder/userfiles/files/50730551919.pdfIn PDF document text
    • https://krusomying.com/data/file/79241314535.pdfIn PDF document text
    • http://esangsok.com/upfile/files/70102321715.pdfIn PDF document text
    • http://cermak-expo.cz/data/files/file/dedon.pdfIn PDF document text
    • https://cakenflowersonline.com/userfiles/file/zekenojapanuxigate.pdfIn PDF document text
    • http://daimarconstrucciones.com/images/admin/file/70865924392.pdfIn PDF document text
    • https://thebookonpersonaltransformation.com/FCKeditor/file/zitixejibu.pdfIn PDF document text
    • https://www.cdscabling.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613f699511e43---99851083051.pdfIn PDF document text
    • http://ketphatthinh.vn/upload/files/kodiwulalodakozimu.pdfIn PDF document text
    • http://dagmar-e.de/userfiles/file/91522505406.pdfIn PDF document text
    • https://careerroots.net/ckfinder/userfiles/files/pelefewipunaratemafugalaz.pdfIn PDF document text
    • http://multiseal.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/16136f6797ca47---fizidijafizipoju.pdfIn PDF document text
    • http://flyingkirin.com/uploadfiles/file/181043535059.pdfIn PDF document text
    • https://novinfasteners.com/userfiles/file/10703614574.pdfIn PDF document text
    • http://unitec-egypt.net/userfiles/file/kexedamogujiwasakove.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=zombie+catchers+apk+modPDF 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_off0000c476.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC476 10824 bytes
SHA-256: c66428d63625eb0ecae55835caa5e734ae3c5346cf230d9985d06e432d980bb2
font_01_sfnt_off0000dd42.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD42 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f554.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF554 16916 bytes
SHA-256: 488e555e5bdd0f7055a5ae75295e6feaedaea34fa2853bedbb1af67f696d42ff