Malicious PDF — malware analysis report

Static analysis result for SHA-256 08ca55dff5e5f55f…

MALICIOUS

PDF

79.0 KB Created: 2021-09-19 22:27:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e2470000fa0e9bb3e486ef499e6f5dc7 SHA-1: eef4daed909608aa5eebea329eefb4307c716cdc SHA-256: 08ca55dff5e5f55f9bfcf2cde7acba744b8a375b961b595ca4b0d6dbcba40acb
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which point to compromised websites or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution through these links. The document body is heavily obfuscated and does not provide clear textual content, but the heuristic firings and numerous URLs are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9903

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://boumqueur-edition.com/upload/fckeditor/file/72427715383.pdf
    • http://yarpb.ru/pic/userfile/xupoledotewagosuge.pdf
    • http://kimbuunguyen.com/uploads/userfiles/file/luwujapebu.pdf
    • https://lederstuhlshop.de/ckfinder/userfiles/files/65564652260.pdf
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/161368b5aa0a74---63695476297.pdf
    • http://keifo.ru/ckfinder/userfiles/files/duduroroduv.pdf
    • http://yildizteknikelektrik.net/resimler/files/50145644343.pdf
    • http://www.moyekolodin.com/files/61304365962.pdf
    • http://hong-tour.com/FileData/ckfinder/files/20210907_32CD8ABF3534FBAD.pdf
    • http://vetcasatenovo.it/userfiles/files/kovuv.pdf
    • http://maidichike.com/upload/files/21615478822.pdf
    • https://fsbulletsandbrass.com/userfiles/files/32982950577.pdf
    • http://nfrostov.ru/upload/files/wapofimam.pdf
    • http://veiligheidssloten.nl/ckfinder/userfiles/files/gesugibosegize.pdf
    • http://xn--80akij1ajew.xn--p1ai/wp-content/plugins/formcraft/file-upload/server/content/files/1613ba42aef266---zofal.pdf
    • https://rabudiagnostic.com/userfiles/files/6010331867.pdf
    • https://oncallanatomist.com/ckfinder/userfiles/files/kasemenimaj.pdf
    • http://allseasonsart.com/uploads/fck_uploads/file/pukupewofotapunuliw.pdf
    • https://leanuslab.com/UserFiles/file/wimapofaniwu.pdf
    • http://studiotecnicomaglio.it/userfiles/files/sutitiwetepa.pdf
    • http://akkoryazilim.com/userfiles/file/buxegir.pdf
    • http://csa.china-led.net/static/editor/ckeditor/ckfinder/upfile/files/22414466626.pdf
    • https://masterok-kovka.ru/wp-content/plugins/super-forms/uploads/php/files/951931462c75ea21419b03cf4663ca11/rivatizibajonal.pdf
    • http://tdsns.ru/userfiles/file/resubibeno.pdf
    • http://gibkrakow.pl/uploads/files/73150313605.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=sticky+lamb+ribs+recipe
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d6da.bin
124c841e5f79433315ec4d285fc72de27bb1bec455c18a0e7f941acc31f6f82b
pdf-font-stream PDF embedded font (sfnt) at offset 0xD6DA 10732 bytes
font_01_sfnt_off0000ef59.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xEF59 16792 bytes
font_02_sfnt_off0001076b.bin
fbdf58b0fddfb2c8e52b6e9c09dd924fda7f9b57e913298d5e583ee2b4380ecd
pdf-font-stream PDF embedded font (sfnt) at offset 0x1076B 17732 bytes