Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf639fd89321c8e3…

MALICIOUS

PDF

42.8 KB Created: 2020-08-17 17:46:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 227c8be97550dd6aff93b4554738fb46 SHA-1: c5e8b84072615c1e72c0492a2eae426b1edded4a SHA-256: cf639fd89321c8e3b6aecba5dcf10ac6257fc024ce44551ae6a4ad91eabe334f
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell T1204.002 Malicious Link

The PDF contains embedded links, one of which, 'https://ttraff.com/pify?keyword=carbonyl+chemistry+practice+problems+with+answers+pdf', is identified as a malicious redirector. The document body, though heavily obfuscated, also contains this URL and appears to be a lure related to 'carbonyl chemistry practice problems'. The presence of numerous other links to Shopify-hosted PDFs suggests a link farm or SEO poisoning tactic to increase visibility. The ML classifier strongly flagged this PDF as malicious, supporting the conclusion that it is designed to redirect users to harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 4

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://ttraff.com/pify?keyword=carbonyl+chemistry+practice+problems+with+answers+pdf
    • http://files.coburghighhistorical.org/uploads/1/3/1/6/131607712/texagopijikiro-pelaxawotiwez.pdf
    • https://cdn.shopify.com/s/files/1/0440/5710/0453/files/kalender_2020_veckor.pdf
    • https://cdn.shopify.com/s/files/1/0438/5269/3669/files/wesamigebadi.pdf
    • https://cdn.shopify.com/s/files/1/0429/4914/8838/files/silugemof.pdf
    • https://cdn.shopify.com/s/files/1/0434/7042/2180/files/vojurenem.pdf
    • https://cdn.shopify.com/s/files/1/0434/3008/4760/files/33477419132.pdf
    • https://cdn.shopify.com/s/files/1/0433/5288/3352/files/fitokakuzabezolomom.pdf
    • https://cdn.shopify.com/s/files/1/0428/0087/3631/files/attic_greek_dictionary.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/

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005bd1.bin
f1ba407913f9f53ae4deaa8be072c4e56b624d4ee757767871ea224c84ef38d5
pdf-font-stream PDF embedded font (sfnt) at offset 0x5BD1 5540 bytes
font_01_sfnt_off00006e88.bin
0de89fea29599bffa9ef0796c98c21eabb2c19c9a273adf563544ba7ef31b24c
pdf-font-stream PDF embedded font (sfnt) at offset 0x6E88 9880 bytes
font_02_sfnt_off0000905d.bin
9f355172d696dda274cac500966718f112ce76951f19577ac4888987ea6471b2
pdf-font-stream PDF embedded font (sfnt) at offset 0x905D 4324 bytes