Malicious PDF — malware analysis report

Static analysis result for SHA-256 c55e20ec460d1743…

MALICIOUS

PDF

77.5 KB Created: 2021-06-28 11:11:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 862986fc83b87a116e2d262f0c156ed0 SHA-1: c9417401c0aa07402359117a78778ddbec0108d7 SHA-256: c55e20ec460d1743e44ec949f2be622cefec8dc03466f5991d46ec5f0f552645
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 CMS upload directories or disposable hosting, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly support its malicious nature. No scripts were extracted, and the document body was unreadable, but the heuristic findings are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9927

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://dichvuketoanvn.org/uploads/files/balexu.pdf
    • https://arizonalightingsales.com/wp-content/plugins/super-forms/uploads/php/files/5cba1457be83705db5bccb76c2a3dfc1/1653867561.pdf
    • https://www.histoiresdegroupes.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d1db900ae50---movikiv.pdf
    • http://sobsai.com/ckfinder/userfiles/files/9206755262.pdf
    • http://mobilephleb.com/clients/2/2d/2d2188d13063160162e6e2bbcdac547d/File/47709710762.pdf
    • https://arerp.kr/data/file///28942407587.pdf
    • http://lotuscourtpune.com/wp-content/plugins/super-forms/uploads/php/files/hva6l36bk2q2qbpt83drtl6kp7/sitovojumujabu.pdf
    • https://earplighting.com/wp-content/plugins/super-forms/uploads/php/files/27e916966baf221ee7990c13e894c169/300404385.pdf
    • https://xlux.vn/wp-content/plugins/super-forms/uploads/php/files/0vuuaepb9pt3ecnk7hrno3kaj3/fudawezojobubiwuw.pdf
    • http://stlnsk.ru/uploads/file/9282346334.pdf
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/160af86888df56---81593890433.pdf
    • http://africansafaris-spain.com/FCKeditor/editor/filemanager/connectors/php/connector.php?Command=FileUpload&Type=File&CurrentFolder=%2Ffile/xumepesafimozo.pdf
    • https://eyestech.in/wp-content/plugins/super-forms/uploads/php/files/f073hq0ucsg3al65n1sp7csj2c/xuribowixida.pdf
    • http://erfolgsapp.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607c584d77b02---netir.pdf
    • http://forter.vn/hinhanh/file/32229554143.pdf
    • http://boothbayharborshipyard.com/userfiles/file/28412312175.pdf
    • http://salkim.com/userfiles/file/bufoxobakejopilajabokatur.pdf
    • http://www.barankayalar.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160cb245471778---gavaju.pdf
    • http://ineke-ott.nl/keramiek-beelden-imagesfile/bamowet.pdf
    • http://www.tenniscanberra.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1609e2c5757ed1---pifazezekugiresawopumavu.pdf
    • https://veterinarycarefoundation.org/userfiles/file/89573328740.pdf
    • http://www.akutrans.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a4896689db3---29036725292.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=trig+identities+reference+sheet
    • https://mediaget.com/userfiles/files/11523975856.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b897.bin
a4ee06dfbf4865bf0791e93f78c712abb02f992b0e9528ae5ddaa940c8eb1cb2
pdf-font-stream PDF embedded font (sfnt) at offset 0xB897 16112 bytes
font_01_sfnt_off0000e222.bin
9d5144547e0b729630886a3ad3ce48e7da84b0115899dd9c2390406af6f0fecd
pdf-font-stream PDF embedded font (sfnt) at offset 0xE222 16092 bytes
font_02_sfnt_off0000f767.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF767 16792 bytes
font_03_sfnt_off00010f7e.bin
6ff48d52bb06ddbd824d6a7e63fe06c3fb57bc1c55e646e35d1a9543f709009a
pdf-font-stream PDF embedded font (sfnt) at offset 0x10F7E 10392 bytes