Malicious PDF — malware analysis report

Static analysis result for SHA-256 833cbf32d89dc638…

MALICIOUS

PDF

84.2 KB Created: 2021-09-22 18:15:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: e600577f7ca1abb00c9e0c58ddd7fcfd SHA-1: f2dd1c67d5b6f522e315968774fb9a19fb52c9d9 SHA-256: 833cbf32d89dc63880967509efda0280bef494912df23865b4dca5ee21167aef
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The PDF file was detected as malicious by ClamAV and an ML classifier, exhibiting characteristics of a link farm. It contains numerous URLs, many pointing to compromised WordPress sites, suggesting an attempt to distribute further malicious content or phish users. The presence of these links and the overall structure indicate a likely spearphishing attachment attack vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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 http://multiseal.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/16141ee097bdab---kukutabaximupusifez.pdf In PDF document text
    • http://yuc-fac.com/uploadfiles/20210914085325.pdfIn PDF document text
    • http://saltokisport.com/uploads/files/1250472743.pdfIn PDF document text
    • https://treasurehunterdetectors.com/ckfinder/userfiles/files/27297758812.pdfIn PDF document text
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1614400db9b541---42793052070.pdfIn PDF document text
    • http://e-sheremet.com/img/28059098316.pdfIn PDF document text
    • http://asupuro.com/upload/save_image/files/70236121292.pdfIn PDF document text
    • http://haokunchem.cn/upload/files/53005497296.pdfIn PDF document text
    • http://tischlerei-schlusche.de/sites/default/files/file/11767110245.pdfIn PDF document text
    • http://amako-ra.com/wp-content/plugins/super-forms/uploads/php/files/d5859185cec7bf18031966798633721f/wegigupobasedewazidez.pdfIn PDF document text
    • https://notofthisgalaxy.com/wp-content/plugins/super-forms/uploads/php/files/hjhkpcjcdhja07ihkf17g7bk91/gopukinekedujuxebegixabi.pdfIn PDF document text
    • https://media-get.ru/userfiles/files/87601554273.pdfIn PDF document text
    • http://www.deadclan.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161420421bd00d---fepelokekojerej.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/161429e7279a6a---pepavolupunamenesorumasap.pdfIn PDF document text
    • http://yangpupark.com/uploadfile/files/pinagusofubifavexunem.pdfIn PDF document text
    • http://adveotec.com/img/file/8524227774.pdfIn PDF document text
    • http://progfin.pl/userfiles/file/lifukajawa.pdfIn PDF document text
    • https://digitaldaya.com/imagenes/file/73735626554.pdfIn PDF document text
    • https://www.pfgpartners.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613ccaaf2eec0---julor.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=instruction+text+featuresPDF 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_off0000e71a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE71A 17280 bytes
SHA-256: f7ba2487245e3e68b8cbcdf7d0e2479334129a31ad73d5bfe83e292edd7bbf18
font_01_sfnt_off000113bf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113BF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012bd6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12BD6 10436 bytes
SHA-256: c04f80ec26eb3a090d2827214f38fc7ab45aba18d034a32e9b36754b46f43293